I have only ever bought two used regulators , only because they came as full kits of gear at a good price, then sell what I don't want [eBay etc], kept one regulator, looked OK , the IP was good with no creep.
The regulator is an Aqualung Core [the only diaphragm regulator I own] had to look it up online for specs , the two 2nd stages breathe very well [did a shallow dive with it] , [ will I strip it ? Can't help myself]. came with a console with compass, SPG and i300 computer in good order, what to do, sell or keep?
This is all "Waffle", I WILL sell it, no question , and dive the regulators I have bought new [last year] or older ones [which I bought new] which I have service myself.
It's life support [Bingo].