[jwa76fleetside]

found this...

1973 - 1976 Door's have different in side handle shorter trim panel that screws do not line up with most of the holes of the 1977-91.
The 1973 - 1976 never had power window's so the knock out steel plate is not there. And there is a few other bolt & screw hole that do not line up. But the door is all most none changed from the out side from 1973 -1991 . The 1977 first year for power window and locks so the knock out plate for the wiring is there unless the door had power wiring. The panels are almost the same size & shape just two holes do not line up and different inside door handles from 1977-1980. So if you 1977-1980 inner door handles you can't use 1981-1991 panels.
For 1981- 1991 the door handles different from other and bolt up different