Newbie Valiant question.

I'm not really into domestics that much(Z car fan), but I have a chance to purchase a 64 valiant and had a couple of questions.
1. What exactly is pushbutton?
2. The girl that is selling it says something is wrong with the pushbutton and the car doesn't go in reverse. Is that a big problem(hard, expensive to fix)?

Push botton is the type of shifter it uses. Instead of a colum mounted or floor mounted shifter it has buttons on the dash board. Very cool looking but wouldnt be the best choice for racing.