Bob, I think at some point in the recent past Gennie went out of business and some distributor of theirs bought up the rights and started building them. That might be why the delays. As I recall, for a while it was impossible to get Gennies or the parts for them.
As for that button on top, yep, it is there so you have to depress it to shift out of park or into gear. The adapter makes it possible to put another knob, without the button, on the shifter, and you simply put your palm on top and shove down to shift.
But they are a little tricky to adjust correctly and just a slight adjustment can mean the difference between going into gear and not. I was traveling on the interstate at 70 mph one time and heard a car revving up near me......it was my car, it had dropped down from 3rd to 2nd on a hard bump in the road !
Don