Yes, the 69-71 wiper switch is different from the 72-76 wiper switch.
I believe the 69-71 switch as a 3-wire plug in and is grounded via a metal plate/tab where it mounts to the dash. While the 72-76 switch has a 4-wire plug (one of which is a ground).
I don't think the mounting are for the wiper switch was changed between the years so it should be possible to put a 69-71 switch into the 72 dash (instrument panel housing).
Or, the 72 switch you have can work in your 71 if you don't mind changing the wiring. The 72 switch will have an L-shaped connector. Starting at the long leg of the L, the color coding of the wires is black, light blue, dark blue (wire colors stayed the same for both years). The extra terminal (out on the short leg of the 'L') is a ground ... you'll have to run your own wire for that since it's not in the 71 harness.