Wiper switch compatability?

I'm trying to remember if you could get the washer option with single speed wipers in 1964. It may be that you had to order the variable wipers to get it. I seem to remember some switches had a black center button on the switch to run the washer and others you just pushed the knob in to get the washer to work. If all the switches have the washer feature whether the car does or not, you might be able rig up some wiring and a pump to do the job. Does your switch knob/post push in against spring pressure? If so, there may be some unused terminals on the switch that operate the washer option.