Depends on the regulator. Most O2 regulators used in the medical profession don't have a "right or a left handed" thread. They simply slip over and tighten onto a poppet on the tank (sorry if I'm not describing this correctly).
I have a medical O2 tank (of course, I use it for medical use on my squad truck), but I have been known to "think" about using it for oxygenating beer.
Medical O2 regulators are also quite expensive--- $100+ (on average) for a "cheapy"
Medical and industrial regulators are very different critters.
check out the link below.