[mr2686]

First off, I'll preface this by saying that some larger pictures would help, but as one of the resident 70's A's fans on the board, I'll take a swing at the one's that look like they're in the ballpark
I believe Dick Williams is a clubhouse, and the following look good enough that I'd want to have someone look at it in person:
Vern Hoscheit (he signed in that spot quite a bit), Knowles, Green, North, Adair, Marquez, Pina, Fingers, Maxvill, Bando, Stock, McKinney.
I'll pass on the Reggie because his early sig gives me fits, but it's quite possible it might be good as well.
Anyway, based on those, I'd say the ball is legit.