Copied direct from Beckett's set summary for the "Special Artist's Proof" set:
A parallel to the Score set, these cards were redemptions of winning Golden Blades cards, which had blacked out boxes readable only with a special lens available at hobby shops. Customers received a Special Artist Proof card while the dealers who sent in the cards for the customers received similar versions called Dealer's Choice Artist Proofs. The only difference is on the Artist Proof logo, which adds the word 'Special' on these versions.
The last sentence is NOT true. The Dealer's Choice AP cards do have "Dealer's Choice" around the AP logo, but the Special APs do not have anything extra.
Unfortunately, the ONLY difference is the thickness of the card, and albeit it's not very thick by 2021 standards, it was about 3 times the thickness of the base cards and Artist's Proof cards found in packs.
Here is a picture of both APs on top of each other showing the logo. The "Special AP" is the top one:
The next image is a photo of the edge. The AP from packs is to the left, and the Special AP is to the right:
Despite what Beckett states, these images show that they are incorrect about the stamp, and the only difference is the thickness of the card. I hope this dispels any further confusion about the Special Artist's Proofs.
-- Dan --
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