Dutch Clark Signed Pro Football Hall of Fame Post Card PSA Slab 42641 The number in the listing title is just an inventory sku for our records and is not the authentication number. This is the exact item that you will receive so please see pictures for condition. This is a post card that has been personally autographed by Dutch Clark. This has been professionally slabbed by Professional Sports Authentication (PSA) and includes a certificate of authenticity from Denver Autographs.