Assistance Requested: Split Back Seat

Hey T@b 320 family,

has anyone ordered the split back seat for a 320s and done the modification yourself?  If so, I am wondering if the seats came prepared for the hinges? I received the seats, but the plywood is 3/4 inch thick and not shaved down for the hinges like the original full seat in the camper is. Just trying to determine if this is correct or if I happen to get seats that were not prepped correctly. Thanks!