The embedded video player on this site is nice in the way that you can framestep clips, making it easy to discern how many frames it's animated at (it's not called framerate, the framerate is 24 fps).

The problem with introducing a tag like you are suggested, is that it apply to almost no cuts on this booru. Almost all the clips uploaded here have variations in exposures.
You rarely find cuts that's not variations of 2s, 3s 4s and 6s.