Ring and pinions are matching sets. So you have to keep each ring and pinion together if that is what you are trying to get at. You can't just change the pinion or it most likely will result in failure.
Also, if you have a different number of pinion teeth, the pinion will change in diameter, which will require a different thickness of ring gear(or even a different carrier). So the 41 teeth ring gears are probably not all the same if they are for a different ratio.
Also, theoretically if you have a 10.5" gear with 41 teeth, it has to be the same pitch. However, what about the tooth angle (both sides), and the curvature of the tooth, etc. It's not as simple as just changing the pinion.