Used Rib/Waffle case gearbox gears in decent shape are getting harder and harder to come by. Since the reverse gear arrangement (along with 1st) in these gearboxes is a "crash" engagement, no synchro, and straight cut, I don't think there is any real concern with a "wear pattern" The front edge of these teeth get battered pretty badly by impatient engagement. Occassionally I find the teeth on the laygear and the 1st gear wheel worn from actual engagement, but not as often as the teeth just being gone from "crashing" the gears. The inside "dog-teeth" which engage 2nd and are "synchronized" with the actual 2nd gear also are frequently worn.
Reverse gears 22G240/22G1114 are available as new. Moss shows them for less than a B-Franklin. Good used ones are also available. I'd sell one for $30 + S&H.
FWIW, having built literally hundreds of these rib-case gearboxes since the late 70's, I have mixed gears for years. Rarely do I find a problem that is "gear teeth match" related. If the gear has noticable wear on the teeth, it gets tossed. Mostly its synchros, dog teeth or some other issue. Not the main drive/driven teeth other than those for 1st gear. Worn 1st gear teeth are a problem.
HTH,
Mike Miller