the 200/2.8, 300/4 and 70-200/4 all use the same ring. I'm sure there are several other lenses that use it as well, but those are the 3 I've owned.
Sure they all fit each other? I tried the ring that came with my 300 f4 on the 200 2.8 prime and it was a lot bigger than the lens area right around area the camera mount.
Doesn't the tripod ring go there?

