I've moved the key mechanism pushbutton to the driverside on my 53, on the push button doors, all it locks is the button itself from being pushed so it works fine and the inside lock still works to. If the Door is locked from the inside (by pushing the handle forward) you can't open it with the key, they are seperate mechs.
Most of the parts houses, Carters, Chevy Duty, LMC sell a matched set of push button mechanisms if you want to have matching locks on both sides.
MONGO
