How to identify which Wiper Motor (2 speed or 3 speed) Should be on 75 Duster

I've been trying to figure this out. When you push in on the button it feels sprung, but I've been told that the answer is no. The car I'm working now had a 2 speed and a manual foot pump for the washer. I've been working with another member to convert the foot pump to an electric momentary switch which I will wire to an electric washer set up. Seems like the best of all worlds to me.

I can tell you with absolute certainty that the 2 speed wiper switch in my 74 Ramcharger is depressed to pump windshield washer fluid.