Seems like there were some television shots of him jogging where there was some "jiggle" in his darker running shorts. The shots were very brief, though.
Also, check out some of the earlier Bonanza episodes now in syndicated reruns. Michael Landon obviously was "without" from the way his more snug pants fit back then. Some scenes had him with "prominence" down his left leg and others did not. Even in the more socially conservative early '60s, seeing a guy on television that did that was unusual--and could well have helped the following the show had back then.