Al talked about his being an Astronaut, and said he was on an Apollo mission which orbited The Moon. The time of the manned Apollo orbital missions occurred in late 1968 and early 1969, at which time Al was previously established as being a POW, or at least serving in the Vietnam War. While at the time NASA recruited Military Personel to be Astronauts, it is unlikely, if not impossible that Al would seemingly go straight from working for NASA to be sent by the Navy for combat service.
After Sam/Bobo climbs out of that nasty dirty pond water, his diaper is completely dry and pure white.
After Dr. Ashton wipes the bananas of the side of Sam's face, the bananas disappear and reappear on his ear and face between shots.