I don't know how you guys are seeing some of those details--where are my bifocals? Now I'm noticing something peculiar about the J-Valves: Lloyd's is up, Beau and Jeff's are down, and Jeff does not have a rod to pull the valve. That could mean: Lloyd used less air and didn't ever go on reserve, or Beau and Jeff were taught not to use J-Valves (as per my NAUI instruction in '69), but then why would Lloyd be using the J-Valve? I'd think since they are father and sons he'd be dictating their use, or not to use. Jeff still could have reached around to pull his J-Valve down. But they don't necessarily look like they've been in the water recently, judging from their hair. But then the whole thing could have been staged.
After reading the other posts I'd say yea, definately an early Calypso J with SPG on Jeff's tank--the tire knob dispells any doubt. I never saw an SPG before 1969 but that doesn't mean there weren't any. Voit seems to be missing from this picture--did they make backpacks? My old US Divers backpack has a vertical handle. I can't remember if my Healthways had an angled handle like those in the pic. It must have otherwise I'd have no reason to hate the angled handles.