The 21 Club?

Friend o'the Archive Steve Schnaper has been sending in some scans of anomalous doings in the 1974 Baseball set, specifically related to certain team cards deployed by Topps. 

The scans started off with thIS Oakland A's card, which had a mysterious "21" printed next to the team name:

The reverse staining shows clear evidence of the card once being from a pack:

Following this, and noting the "2" and the "1' above are from two different typefaces, sans-serif and serif respectively, this Pirates card turned up with either a sans-serif "11" or two parallel lines in the same general area:

There's also a back scratch froma  pen on the card that Steve advises was not applied post-factory (hard to tell if that' s another 11 or not but it's pretty sloppy either way):

The A's card was sent in to SGC and determined to be authentic and garnered a grade of 4:

Steve also says he has found a Red Sox Team card with a front dot in the same general area as the other two markings and mentioned the Pirates card has now been slabbed by SGC.

Rich Mueller at Sports Collectors Daily posted about the A's card a little while back and a friend of mine with a LOT of 1974 team cards looked through his stash to no avail; neither had ever encountered anything like these oddities before.

If anyone out there has a clue what's going on here, please reach out!