Joe Montana Autographed/Signed 1991 Pro Set #3 Trading Card BAS Slab 33881 The number in the listing title is just an inventory sku for our records and is not the authentication number. This is a 1991 Pro Set #3 trading card that was personally autographed by Joe Montana. This was professionally slabbed by Beckett Authentication Services (BAS) and includes a certificate of authenticity from Denver Autographs.