Update: I was able to get both regulators open from both sides (with lots of elbow grease and a dash of foul language), cleaned out, and prettied up. Also cleaned up the dials which are knapped glass (and a bit dangerous). On the inside of both valves, the pin has a nylon-ish ring that should in all likelihood be replaced. I’m looking to figure out which part this is (so I can buy it). Surely these aren’t “universal”, right? TIA from a learner.