Thanks for the info! a few people so think that they are custom keys for some company. Apparently that wasn't uncommon 'back in the day'.
It'd make the most sense, some sort of typesetting company.
IF you have a whole set, I'd love to see pictures to help document that they exist. There is very little out there about them, but they are more than a one time set.
Heck, since no-one else has documented them, you might even get to name them. Like Kish got his name on the Kishsaver.