Looks like a Conshelf XII, made from 1972-1976, but you photos are blurry. From the one of the 1st stage and the number of ports I'd say it is early 70's say about 72-74. Look for the serial numbers on the 1st and 2nd stages it should read something like 74-12345. The first 2 numbers are the year of manufacturer.
Nothing wrong with the reg and parts are readily available and rebuilding it is easy. Internally, the 1st stages uses many of the same parts used in USD regulators from the late 60's up to the 2000's.
The first stage rebuild kit is Aqua Lung part number PN 900001 which is used for the 1st stages for the Conself XII, XIV, 20, 21, 22, SE2, SE3, and the Titan so if you take it to a LDS that says they can't get parts for it anymore you can call them jerks and know its time to go to another knowledgeable, or honest, dive shop.