Is a 3 speed wiper transmission teh same as a 2 speed?

When I converted to three speed wipers I used
3 speed motor P/N 3431624
3 speed switch P/N 3488764
3 speed wiper arm/ crank P/N 3431687
I didn't have to modify any of my original wiring just plug and play.
If I remember right the way that the wiper arm connects to the linkage is different depending on what part number/year wiper arm you get.
Using the above P/N wiper arm I did not have any problems connecting to my stock 71 Scamp 2 speed wiper linkage.