75 Duster vs 71-72
Not all 1975 models had the larger bolt pattern wheels.
Electronic ignition, catalytic converters, crash beams in the doors for better impact resistance....as mentioned, different interior door handle placement, interior door panel design, one piece cardboard headliner, etc.
All Dusters are great looking cars, in my opinion. I had a '74 that I modified to look like a 70-71 though.