Tom Mathews is one of my favorite models. I have not been able to find that many photographs of him. He was a model for the Athletic Model Guild. I believe the one of him posing with a bow is by AMG.
Keith Stephan was clearly a massive bodybuilder. I first saw him in Bob Mizer's Physique Pictorial magazines.
Bob Mizer is considered the father of beefcake. He founded in Los Angeles in the 1940's the Athletic Model Guild, which first photographed male models to promote them to artists, photographers, etc. Later, the photographs were collected into the digest-sized Physique Pictorial, which also featured the work of other pioneering photographers and artists.
Here are several photographs of one of my favorite beefcake models, Robert Fedell. Many of these photographs first appeared in Volume 24 of The Male Figure magazine by Bruce of Los Angeles.