68,69,70 Dodge and Plymouth B body doors all interchange physically, but:
The 68 doors have the door lock push button at the far rear.
The 68 hardtop doors use a bolt in door glass up stop that bolts in near the center of the door.
The 69,70 doors have the lock button moved forward, plus,
The 69,70 doors have a bellcrank from the lock button to the latch, so the door also has a pair of holes to mount the bellcrank pivot.
The 69,70 door latch itself is different, in that the door lock button operation is side to side, where the 68 latch operation is up and down.
The 69,70 hardtop doors use a different bolt in rear door vertical channel that incorporates the door glass up stop.
The 69,70 hardtop glass has a hole with a plastic insert near the lower rear of the glass that contacts this vertical channel.
The 68 hardtop door glass has one less hole than the 69-70 door glass because of the up stop differences.
You can use a 69-70 hardtop door glass in a 68, but cannot use a 68 hardtop door glass in a 69,70 unless you also use the 68 up stop system.
I don't recall from memory if the coupe glass had the same differences between years.
So while the 68-70 doors will all bolt on, there are a lot of little differences mainly in holes, and with patience, any door can be made to fit in these 3 years.
