Yes, you have to use an 83-84 R shifter to match the frame, AND you have to replace the shifter shaft (81-82 R shaft is longer and won't fit in the frame)... OR you have to do what I did and cut down the 81-82 R shifter shaft. I cut mine with a cutoff wheel because I didn't have any use for the first gen shaft because I don't have a frame from those years... Either way you go you still need a different shifter... I wouldn't recommend cutting the shaft like I did, but they are hard to find and weren't cheap when found from what I remember.
(See the few posts directly above yours for explanation and pictures.)
Hope this helps!