DrSteve:Well I have to say my LDS refused to service my wife's Legend because:
a. It wasn't purchased from them
b. It was purchased second hand
That is a joke, and one that means I won't be taking anything to them for servicing or tank inspection again. OK the price for my reg (also purchased second hand, but they have no problem with an old Conshelf) and tanks is minimal...but it's also easy money, they just lost! I'll support my LDS when they support me!
Are your regulators a brand that your LDS carries? If not, they may not be able to get part easily but they should have a repor with other shops that can service it/them and should volunteer to do that for you. It may cost a little more for shipping though.