I've poked around and found several old auctions for advertisements similar to this one. They were all printed in black and white and the players are identified as well:
https://goldinauctions.com/lot-16007.aspx
I've seen window advertising like this Goudey display as well. Full color cards but again the players are identified:
https://catalog.scpauctions.com/Scar...-LOT52584.aspx
Cracker Jack original advertisement also identifies the players:
https://www.milehighcardco.com/spect...-lot44519.aspx
My opinion is that these are unfinished cards that were cut from original sheets. Whether that makes them proofs or something else in between, I do think that is the most likely origin of them. The lack of player name and team name indicates that to me.