So its a normal LC then

Let me check. I know 6th gear on the RD has 4lO part numbers and the RZ ones are 29L so I don't think its a straight swap. I believe the RZ ones are wider to stop it wearing as quickly.
I guess you don't know if its the input or output gear until you get it pulled apart? You would think it would be the gear on the input shaft as the output gear is splined and rotates with the shaft
A a friend of mine did have a complete transmission as there was someone else in the VRRA looking for one. I can see if he still has it.
I also think there is a brass bush on that gear. I wonder of it would be possible to make one or just replace it with a needle bearing.