Mike Mussina Signed Baltimore Orioles 1991 Score Trading Card BAS Slab 10 29575 The number in the listing title is just an inventory sku for our records and is not the authentication number. This is a 1991 Score #383 trading card that was personally autographed by Mike Mussina with a 10 grade autograph. This was slabbed by Beckett Authentication Services (BAS) includes a certificate of authenticity from Denver Autographs.