Vintage equipment identification

[AandA]

PLEASE HELP ??? ??? ??? ???

I've recently come into possession of an older single hose regulator set-up.  I think this one may even pre-date my Calypso J regulator I had as a kid.

I hooked it up to a tank today, pressurized the system, worked the purge a bit and breathed from it...not too bad really.

My dilemma is that I have no idea when it was made or which version it is.  I'm kind of assuming that it was probably one of the very early single hoses manufactured by Aqua lung, but would REALLY like to know more.
Thanks,
Art