All doors are the same, except between 2-door and 4-door cars. I have a 1972 door on my 74. The inner door handle and opening latch are located in different places and have a different design. I think it changed in 1973 or 1972. But the doors fit.
The doors interchange, but there are minor differences. Early doors are very lightweight and have the early door panels. They lack safety reinforcements put in by law around 72 or 73... In 73 they changed to different door panels and latches. The 73 doors I have seen have provisions for both door panel styles. Then in 74 they became late style only. So... Early doors=early panels/latches 73 doors=go both ways 74-77 doors=late panels/latches Edit: I don't know for sure, but I have heard that the early, non-reinforced doors, have the mirrors mounted further forward on the door than the later ones.
