1968 Dodge D200 with a 318 from who knows where

That was no resin.
Back then many cam gears were nylon coated to cut down on chain noise.
And if in fact the damper is missing the outer ring DON'T RUN IT. REPLACE THAT DAMPER
There are 2 places in California that offer rebuild services, with lifetime guaranteed. Damper doctor e damper dudes. I've used both.
Without the outer ring you're not damping any vibration. Basically it's no longer a "damper".