I highly suggest you don't rebuild the regs and quickly get rid of them. .....otherwise you will get the vintage bug which is uncureable and expensive.........I know 10 regs and many many dollars later with no sign of it stopping.
Seriously, I love the old regs and dive them most of the time. Like Paladin said, somewhere in the $175-200 range in parts and another $70 if Bryan does the job.
Vintage Scuba - Vintage Scuba Gear at Vintage Double Hose For your first one, it's not a bad idea to let him do it just so you know what a properly tuned DA dives like. You can get by with less but the old hoses tend to be a bit stiff to suit me and def replace the diaphram with a new one. They are made of better material and worth the cost. Some things like the band clamp are optional but the C clips are a pita if you don't have the correct tools (I do and still remove them first thing). From there the sky is the limit, you can have it totally rechromed, new labels and a Phoenix mode....now that is a pretty reg.
There are several other items you need to consider as well. Since there is no HP port on a DA, you will at a minimum want a tank with a J valve on it along with the rod. A better idea, esp for the new vintage diver.....that is kind of a strange idea...new vintage, anyway......is to get a banjo fitting. Basically a banjo installs between the tank outlet and the reg inlet to allow you to tap off HP for a gauge. You should also consider a vintage back pack.... which requires you to learn no BC diving, another vintage skill not taught today. New BCs are not designed with DH regs in mind and do not allow the proper positioning of the reg and tend to allow the tank to seperate from the divers back. You can dive a DH reg with a new BC but don't expect the best preformance if you do.
Once you get the old reg restored, find someone local who dives the old regs to mentor you. They are different beast and require a slightly different diving style and proper body positioning to dive their best. If you are unfamilure with them the odds are you will not like them without some guidance. You won't die as you will no doubt be told but you will also likely not be happy with the reg. At an absolute minimum, before diving a DH reg, come back here and get some guidance from the members of the vintage section.
There are some excellent vintage divers here and on Vintage Double Hose who are more than willing to help in any way. Some of us can be a bit crusty but having dove with a lot of them, once you get past the exterior, you will dive with no finer bunch of guys and gals. Get the regs restored and come dive the way Mike and Jacque intended us to.
Hurry up Sand Dog VIII !!!