079 / 799 Baseplate
General Information
The following information has been collected from original newspapers, catalogs, and magazines, some of which are freely available for reference below. The rest can be found in the site’s gallery. No aggregate catalogs (BrickLink, Brickset, etc.) were used.
Advertised Part Count(s): 1 pieces
I don't need a source for that, I have it on good authority.
The 079 was US exclusive and did not release with the 799. They have been combined into one catalog entry.
First Year Confirmed Available:
1965 (799, USA)
1969 (079, USA)
First known appearance in the 1969 idea book.
Unknown Release Year (799, Canada)
Most Likely Retirement Date: 1971 (USA)
Both the 799 and the 079 retired in 1971 in the restructuring of the LEGO Samsonite line. Appears in 1971 dealer catalog.
Possibly 1982 (Canada)
1982 Canadian Samsonite Catalog
While it does not appear in the 1983 catalog, 1983+ production is possible.
Retail Price(s): $1.50 (USA)
Rarity Score (Rarity Index): 4/7 (considering finding the US cardboard top)
Known Box/Packing Variants
The original 799, only when it released in 1965, came in a sleeve imported from Denmark:
These can be differentiated via their stamp "Printed in Denmark". Presumably, the US imported these baseplates for the 1965 season as they did not yet have the mold to produce them.
I do not know if other countries had similar 799 imports. If surviving examples have their price, which the example above does, that also helps corroborate a US version compared to other countries.
For 1966 onward, baseplates were produced with this card glued onto the board, either the front or the back. Usually you'd expect the front, but I have a 799 that was glued on the back, meaning that they could've came either way:
Then there is the 1969-71 US exclusive 079 with the green 50x50 baseplate. It's exactly the same as above but with a different number.
Then we obviously have a Canadian variant. I believe there will be several of these, but I only have an image of the one:

Contents
This entry is specifically for the plain 50x50 baseplate, which was sold for both regions. The grey version was available in both countries, but the green color was only sold in the USA under the 079 number.