All 72s came with right side turn signal levers; this lever also served to turn the wipers on and off (just on/off, not low/high speed--that was the lower right dash switch) and also the wash/wipe feature. The dimmer switch was always on the left on 2002s, even on the 74-76 cars that had left side turn signals.

From your description I suspect that someone has merely swapped sides with the two original levers. Easy enough to do if you move the "finger" (the thing on the back of the steering wheel that cancels the turn signals) to the opposite side. On roundies, the dimmer switch only selects low/high beams, plus has a heedlight flasher feature. There are two styles--early cars had individual spade terminals; later ones (like yours) have soldered-in wires ending in a multiprong plug. You should be able to use any similar dimmer switch from a later roundie--it should plug right in. And you should also be able to swap your levers back to their original sides by simply reversing them and their wiring harnesses (and moving the "finger").

cheers
mike