One of my high school cars was a 64 Dodge 440 with the slant six and pushbutton gear selector, while a good friend had the 63 Dart convertible like your wife's car, only in red. My pushbuttons were rectangular, Alan's, like yours, were round. Liked the pushbuttons..., so different from everything else. One weakness, the selector cable seldom broke, but the seals at the transmission end would begin leaking transmission fluid, so needed replacement.
This will be another fun one to watch...
Have fun,
Lance