Very interested in details; Older Dahon Speeds (mine) had a mount for compact/rapid-rise but no conventional mount (which is why I had to use a claw-mount derailleur), later steel frames had mounts for both (with integral conventional mount if a steel frame), then later still steel frames were only conventional mount. The aluminum frames (Mariner, et al) were only different in that they had a compact mount, then went to a separate conventional hanger (steel) that fit under the nut/quick-release plus a bolt and could be replaced if damaged, I don't *think* they ever used an integral conventional aluminum mount; That last style separate hanger, fit into a recess on aluminum frames; I don't know if you can just slap it on the outside of a steel frame. I think steel frames did not use a separate hanger, as that recess would have thinned the dropout too much, but I could be wrong about that. I looked for a hanger like that, hard to find, and they were more expensive than the whole derailleur with the claw mount. Which, though dirt cheap at $13 at the time I think, has worked amazingly well.