If it doesn't come with a certificate of authenticity then it loses most of its value.
So Hawthorne lied to its members and committed fraud all for a few pennies, how pathetic.Even then, you are very lucky if you actually have "the" jumper, not a pretend one.
At the Hawks BNF this year, the jumper Hodge wore in his last game was on the stage in a frame, for auction. Sitting in front of it, Hodge accidently told the crowd he had given the actual jumper to Ruffy as a gift. Hodge had no idea what he had said.