radio interchange question

I have been looking at a modern radio to fit in my 1970 Dart dash with no alteration of the face plate. I have been considering one from Vintage Radios - KHE-300-USB 1970 Mopar. I called today to order one and the guy told me that it would not fit a 1970 Dart - That it would fit a 1970 B-body and a 68-69 A body, but not 1970. These are all knob radios we are talking about, not thumbwheel. I would swear that the 68-72 A-body radios would interchange - am I wrong?