My 2 interior panels on the inside of the quarters won't fit. The seatbelt is in the way of it actually installing all the way. Are these for a 4 door? Speaking of seatbelt, the seatbelt won't even reach the receiver and I don't believe the seat is even up all the way (seat doesn't move).
You have the wrong year panels. 4-door don't have panels...they have about a 6" piece of trim next to the door's edge
There are 3 different versions of rear panels for a 2 dr. First set are the 70 to some very early 72s. They are basically flat from the arm rests to where the bottom seat cushion touches the panel. In 72 they added retractable seat belts so the side panels have a large bulge to cover the retract mechanism and a slot for the belt to come through, below the arm rest. Most 72s and all 73s have this panel. The lower seat cushion also has cutouts in the ends to go around these bulges. In 1974 they went to the 3 point harness for the front and the retract mechanism was embedded partway into the sill plate for the front belt. So the sill is wider and the front of the rear panel is wider where it mates to the sill to blend in. I used to have a tech article on here about these differences with pictures.
Wait, I have a 72 with a shoulder and lap belt harness...the 2 point harness. But the panels are the 72-73. I guess someone tried putting a later harness in there, but it's weird how it doesn't even reach the receiver.