There are 10 visible autographs. I can only positively identify 7 (maybe 8) of them. Seems 6 of those 8 players would/could have played in the 1978 Super Bowl, however 2 of them were definitely not around in 1978. Those 2 probably signed the hat in 1980, or at the latest, 1981.

Drew Pearson #88 - Hall of Famer

Butch Johnson #86

Jim Cooper #61

Ed "Too Tall" Jones #72

Andy Frederick #71

Robert Newhouse #44 (???)

Legible 1980/81 signatures:

The remaining 2 signatures are very faint but potentially could be figured out by an expert and/or someone who has more time to spend on this rabbit hole than I already have. :-)