Fleer did a couple of mail-in posters in blue like that for their Stamps and Stickers. I believe the idea was that you'd order the parge poster and then stick your stamps/stickers on the poster in the right spot, like the albums.
Some of those have been cut apart and sold as proofs, but they are simply a poster cut.
http://1978theyearitallbegan.blogspo...ps-poster.html
http://1978theyearitallbegan.blogspo...r-sticker.html
Not saying those Donruss are not some sort of proof, but this is very similar. I grabbed one of the 90 Donruss "proofs" from ebay recently myself. Same seller had some 82 Donruss that were also blue. They were cheap enough to not worry if they do turn out to be fake, but this guy had a lot of proof cards too.