Yes, that is definitely a 108 and a Mk-8.
The Mk-8 is basically the same as a Mk-5 without the swivel turret.
This is what the timeline says, and in this case I agree with the Scubapro timeline.
Note: there are plenty of other errors that we have verified, but Scubapro have not corrected them.
1979 — 1984
MK8
The MK8 is another alternate version of the MK5. It was on the market from 1979 to 1984. The primary difference from the MK5 is that the MK8 did not have a swivel. It existed in two versions: the first generation had a small yoke, wing nut, one high pressure port and one low pressure port, and the cap had a rounded appearance; the second generation had an S.P.E.C. cap with a flat bottom, four low pressure ports and two high pressure ports.
The second stage is a basic down stream demand valve. A very solid simple design.
Both the first and second stage can be service and they it would make a nice regulator.
VintageDoubleHose.com carries all the service parts and needed documentation for service, or he can service it for you if you don't want to do it yourself.
Some local dive shops are very likely going to say that it is no longer serviceable. You may want to avoid that type of LDS.