This has been discussed before, multiple times, and I am now
PISSED!
But seriously, I think PSA does have a notation if the card is fake. The flip would say "? Authenticity" or something to that effect. Typically, I would stay away from these, and you have a reason to be wary. However, one good thing about this auction is the seller, Memory Lane, is reputable and not in the business of pulling this type of scam (unscrupulous sellers would switch the Gehrig with a reprint and try to pass if off as real, using the "evid of trim" flip as a decoy to put buyers at ease).