I am betting you have Five ply shells. Speckled gray interior. Made in Fullerton CA, 1975/very early 76. The Dynasonic has no dampener, I would like to know the serial of that specific drum. And please post pics of your Dynasonic. I am very interested in that drum, whats on it, the fact it has no dampener, what the top of the throw off knob looks like. Also, what do you know on the history of these drums? When exactly were they purchased new?
Now..... if all of your drums fall in these five digit serial number ranges, I would say thats a set.
The reason your drums interest me is that I am trying to establish an accurate serial dating for Rogers Dynasonics and Supertens for the early Big R era. Your drums are first year issue, and the dynasonic is a 2nd generation transition. There werent a whole lot made, but they are all like yours, without a dampener. As of right now, that doesnt increase value to anyone. The odd thing about your set is that you have two different sized bass drums.