Al Urban took publicity and magazine photos for a number of competitive bodybuilders, and this unknown model certainly might have been one. I have searched unsuccessfully to figure out who he might have been. The oil here is a bit excessive, but the man and the photo impress well.
Edited to add: Frequent behind the scenes blog collaborator and contributor Bryan B. sent me an email identifying this model as Louis Abele, and that's right. A version of this photo with painted in white trunks made the cover of Strength and Health magazine in 1940. Thanks, Bryan!