I'm sure someone will correct me if I'm wrong, but I believe all Sportsters shifted on the right, copying the British bikes that they competed against, until 1976, when shifting/braking was standardized in the U.S. The reason for right side shifting was due to the flat track racing, which always ran counterclockwise, making it more suitable to have the shifting down on the 'high side' of the bike as it went around the oval, with the left leg dragging the corners. The '76 Sportsters and '76 Triumphs are not the most desirable bikes to have, as their shift linkage was mickey-moused together to make the change needed without redoing their trannys.
The other Harleys, to the best of my knowlege, shifted on left. Some Indians had their hand shifts on the right.
It was actually '75 for the XLCH (sporty) moving shift to left. I wouldn't call it mickey mouse and never had any trouble from it on my '75. I think it was the brake cable that was kinda chessy if memory serves???
I was in a neighbor's basement a few years ago and there sat a dust covered 73(or therabouts) Sporster with under 4500 miles on the clock. I asked him why didn't he get it out and ride it. "Oh, I don't know, maybe someday." Across the road on his land sits a 56 Ford F100, a 56 Chevy and an old Studebaker 4 door. They are rusting away too.
Yep, I was off by a year, as my two Tridents are both mis-registered by one year. My T150 shifts on the right, and the T160 shifts on the left. They are registered as a '75 and '76, but year of production was '74 and '75.