The USD/AL is a Conshelf, a very good reg even by todays standards. You have the Supreme version which was/is environmentally sealed. That model most likely has the silicone fluid chamber in it. Unless you dive very cold water it is NOT necessary to keep the seal or you can upgrade it to the later dry one. All the parts you need to service it are easily available both from Aqualung ( dealer service) or VDH has all the parts if you care to DIY. The Conshelf first stage is about as good a first stage as you can get, don't dismiss it just because it is older and/or not "cool". The Conshelf was (is??) the reg of choice of the US military well past when it was sold to the general public.
The Dacors unfortunately are a different matter. That appears to be a 900 series first stage. While some aftermarket parts are available for Dacors, it not that easy. Dacor was bad about changing designs within a model and you have to have the CORRECT version to go with the other internal parts. The only way to tell which you have is to open it up. Bottom like you might get lucky and you might not. The second stages are a different matter, most use common generic parts so servicing them is not a problem and contrary to what some may tell you, they are actually quite good second stages when properly set up.
