wb4tjh,
First, your Aquamatic is a unique regulator, and if the rubber is okay, it probably doesn't need much unless there is corrosion. Saying that, I would not dive this regulator in other than very controlled conditions, such as a pool. It is a hard-breathing regulator, with small exhaust ports. Also, the second stage diaphragm is held onto the regulator simply by tape and a rubber piece over it--not a really good idea. I have one, and will keep it because it was really the first North American single hose regulator. But I won't dive it in open water.
SeaRat