Thank you Jason and others for the last minute advice. TBH there are approx 80 GPCs in all with 3 Ott's, 2 Kleins, Teddy Ballgame, those you see here and many more.
I'm sure there is a chance that some might be signed by secretary, ball boy, or clubhouse manager etc.... but there are plenty of lesser names so I'm feeling good overall. Most date from 1941, have a return address and are clean so I'm pretty excited! Will update Tuesday!
Peace, Mike