More Corrections and Refinements!
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One of the joys (and pains) of extensive research into a particular subject is that you'll inevitably come across something that raises a question that you've never thought to ask before. Or someone kindly corrects a previous idea, or points to new evidence completely wipes away previous mysteries.
There's a neat spread of all of these today.
Detroit Production 1961-64
After having completed work on documenting the history of the Samsonite Loveland Plant (1965-1972), I wanted to create articles documenting all Samsonite plants, working backwards from Loveland to finish LEGO coverage first. So Detroit, Stratford, Denver, etc. They're incredibly under documented, and there doesn't really exist any such source, contemporary or modern, delving deep into their histories.
Since the LEGO Samsonite story began to be documented online, the story was that Stratford, Ontario produced all LEGO elements for both countries. After a shipping label for a LEGO Samsonite set was found with an Ecrose, Michigan address, the story was updated that Samsonite's Detroit plant served as a packing house for parts produced in Stratford.
However, I no longer agree with such. Detroit produced LEGO elements for the US market since the beginning.
According to Modern Plastics, 1962, "the majority of the parts are molded by Shwayder at its Ecrose, Mich., plant, and the company expects to consume approximately 1,300,000 lb of cellulose acetate this year [1962]. Several components are now imported from Europe, but all parts will eventually be produced in this country."
With some new sources, as well as quotes such as the one above, it is essentially confirmed that Detroit produced LEGO for the US market. It's an incredibly small detail in the grand scheme, but I find it immensely important as a representation for how Samsonite's history has been previously documented.
Early LEGO AFOLs were able to confirm LEGO production in Stratford in the 1960s, and Samsonite's Detroit plant wasn't known to the LEGO community until later. So the assumption solidified into fact. There is no contemporary source that reports Stratford produced for both countries, imported pieces, etc.
Regardless, something to correct sitewide.
I've written an entire article on the subject: Was LEGO manufactured in Detroit from 1961-64?
750 Educational Set
The 750 Educational Set was known to have two box variants, a wooden box and a golden box:


As the golden box was not known outside of that one example, I theorized it to have been a contest prize variant, used to fulfill contest prizes in Canada via mail. There was a ton of circumstantial evidence supporting such, including the gold coloring.
However, a 1964 Playthings announcement of the 750 completely blew that out of the water, making me realize the gold box is actually the American version:

Which cleared up much of the mystery, to put it simply.
In retrospect, I remember remarking that it was odd that the only 750's that had been found were Canadian wooden boxes (at least two known) and the gold box. I was so convinced that the US version would be in a wooden box as well, I missed that the gold box was the US version.
Del Monte (and other promotions)
This one has so many facets, I'll try and stay concise.
It all began with an article being emailed to me, one that I'd never seen before. Published in August of 1973, it reports that Samsonite's LEGO inventory was sold to Ad Service Co. of Denver:

Looking into this further, a number of things suddenly clicked into place. Why shipping labels after 1971 had a Denver P.O. box, why/how the Kraft promotion continued after Loveland closed into at least late 1974, etc.
Among finding out about the 1973 promotions for Kraft, Del Monte, and LIFE, I then stumbled onto some newspaper questions about the Del Monte LEGO Promotion (1972 & 1973). Not only was I able to conclusively confirm the theorized 1972 date, but I finally found the exact product it was carried out through:

And so, the Del Monte mystery is no longer much of a mystery.
There is, of course, much more to look into regarding all the different Kraft/LIFE promotions.
P&G Promotions
Of particular interest to me is the Procter and Gamble LEGO Samsonite promotions, as they are much less documented and much rarer than i.e. the Kraft promotions. A complete collection (as far as is currently documented) can be seen below:

Three of the sets are Oxydol sampler sets, which were already known. The newest member of the group was the 93-Piece Set, which had no known P&G product it was advertised/distributed through.
I kind of left it at that, the set exists and was distributed through some as of yet unknown P&G product. It didn't sit right with me, but there's not much more to do without more information.
Since then, I learned that P&G did not only distribute promotional premiums through their own products but also local/national sweepstakes. With literal thousands of prizes, and a confirmed appearance of Samsonite luggage within a 1968 sweepstakes, it seems very plausible to identify the set as a sweepstakes prize.
Elements of the set support this, including the shipping label of the box itself. It is the only promotional set I'm aware of that doesn't have a return address.
A full article (that is currently not yet public) going over this investigation can be found here: Identifying the Unknown Procter & Gamble LEGO Promotions.
Epilogue
You may notice that a lot of these mistakes have something in common: assumptions. It isn't that an assumption is inherently bad, they were oftentimes build on patterns/previous behaviors of Samsonite, it's only that assumptions in lieu of evidence are not always correct. We have a pretty even spread of assumptions that turn out true and those that evolve, so I don't mean to impress that it is problematic or an assumption will likely turn out to be false.
That is why I find transparency to be important. Assumptions, where appropriate should be marked accordingly, whether by words like 'likely' or 'maybe', and evidence should be honest.
You may ask why we should allow speculative information at all, especially when they have misled us in the past. The P&G 93-piece set is a good example of this. It gives us a body of evidence that tells us exactly where to look, what should confirm our theory, and what would refute it. It essentially gives a falsifiable hypothesis, rather than a vague "maybe it was through a P&G product". This way, a reader knows what isn't yet confirmed, and can investigate for themselves for what they might think happened.
Ultimately, it's not a bad thing to correct yourself. It makes me much more confident in the information onsite, as it is constantly being put up to the test in the face of new or previously unknown evidence. I also often take some time to go over how others or myself were previously misled on a topic, as I find that to be extremely interesting from a historiographical persepective.
This is the reflection I wrote after realizing the 750's gold box variant was not what I originally thought:
"I find the evolution of my understanding of these sets as an excellent case study as to how correction is to be handled. 'We thought one way previously, this is why it was incorrect and this is the data to support such.' It'd be much easier to simply erase the board and start over, but it would lose a level of viability, in terms of demonstrating the experience with the question being asked. I didn't get it completely right on the first try, and that's okay. I signposted everything that was speculation or assumption as such, which is equally important."
"This archive is not meant as a static 'this is the way everything happened', corrections and rewrites are more than welcome and transparency on that is one of my upmost priorities."
"It is to take a step further than encyclopedic reconstructions and retellings, it is to teach primary source reliance, to question that which isn't supported and build ideas on what is left. Challenging ideas both in the archive and elsewhere with good evidence and logic. While not every source is wholly a source of truth, it is through the continual compilation of them that we can continue to reassemble this story accurately. If we stopped yesterday, it wouldn't have met those standards."
"A simple way I think of it is that I may have been wrong before, but at least I'm not still wrong."