I'd like to add this card and there are two sources listing five players in this set. A PSA population reports shows five names:
Rich Allen
Jim Brewer
Steve Garvey
Duke Sims
Bob Valentine
The collectors.com website links to Ebay and I see pics of the same five players.
The only question is whether or not this set had MORE than five players. I don't know all the online sources. I wish the library near my parents' house was open ... they used to have a thick paperback card manual from the '80s or '90s that might have listed this set.