Rear Interior Side Panels

There are 3 different versions. 70-71, 72-73, 74-77. The black panel on the left is from a 70. Starting in 72 the rear seats had retractable belts. The side panel was ballooned out to go around the retract mechanism and the belt came up through the panel, this is easy to see in the red circled area. 72 thru 77 all have this set up.

Then in 74 they added the retractable seat belt/shoulder harness assembly which is embedded in the floor kind of half under the door sill. The plastic trim that covers this, stuck out a bit, so the rear panel was flared out to blend in with it. You can see how much wider the panel is in the circle compared to the black one. Plus note how the 70 panel has a kick out behind the circle whereas the 74 is smooth. So all 74-77 panels are wide like this.

Rear Ashtray location also changed in '72.

That is all there is to it. In summation, the 70-71 are flat with narrow sill, 72-73 have the retract bulge with the narrow sill, and 74-77 have the retractor bulge and wide sill.

Also the rear seats are grouped in the 70-71, and 72-77. The corners of the rear seats starting in 72, are scalloped to go around the bulge in the panel.