If they are both "9C" motors (type, not brand), then they will probably both fit in the same rotor, but the distance between the axle shoulders for the covers is probably different between a front and a rear.
So while you can probably swap the rotor and wheel between the two stators, you will probably have to use each one with it's own covers.
Another issue is that the axle itself may be shorter on the front motor, so even if you used spacers on the axle to make the shoulders "extend" out to meet the rear covers (so the wheel doesn't slide side to side on the axle), there might not be enough axle length to reach out far enough on the dropouts to get the axle nuts and other hardware on.
The axle length you can measure without even taking covers off, and you can get an idea of shoulder width by measuring from side to side on the covers where the axle comes out of them, and see if these are problems you'll have, before you go any further.
