The guy behind all of these fake Mantles has evolved his game.
He can make the slabs and the flips identical to PSA's right before they released this most recent version. All serial numbers and barcodes will match as well. He will take clean looking cards and TRIM them to look sharp. To protect yourself from this scam, measure your cards and see if you can find the same serial number sold in the past on VCP to compare images.
This guy is tucked away down in Mexico, doesn't come to the states, and uses unsuspecting pawns to deal his creations. I obtained a lot of information about him through e-mail and phone calls in the past but he cut me off when I shared some of the info to protect people from being scammed.
Look at all of the following pictures. Every single one of these is a fake slab and flip with a trimmed card inside. The source of these is same source of the PSA 9 55 Clemente that was headlining the most recent Clean Sweep auction.
Be careful who you buy from and do your homework.