The 68 doors have the lock knob at the rear of the door. The 69-70's have the knob further forward. They will interchange. It was moved forward to make it harder to pop the lock open with a coat hanger thru the gap between the front/rear window of the hardtops.
I had to modify my post...the pic below shows the more forward position..only 68 is at the back, so 69-70 is the same
69 runner below