Well the regular issued cards were on white stock. So it probably wasn't a printing error as it would still be on white card stock. Are the cards the same size as regular ones from the same set? There are a few different ones you have? IDK what they are but perhaps printing proofs? If you would be interested in trading one of the Bird/Johnson rookies I would be very happy to get one as I collect oddball and error stuff and these certainly qualify!
Jim
Jim
![[Image: hgSw1.png]](http://i.imgur.com/hgSw1.png)
Looking for 1990 PRO SET football variations.
Especially 666 Steve Young!!!!