Like he siad, but the 72 fenders are really a one year fender due to the maker light style. 72 was the first year for those plastic generic sidemakers and I think they were even hung higher up on the fender than the 71 Style. The inner fender on the passenger side of a 72 Dart/Demon has an indentation for either the charcoal canister, or, on / cars, it allows more room for alternator adjustment.
The grill in the 71 is the same as a 70 Dart, except it is blacked out. The 72 Grill is again a one year grill. The 71 Demon 340 cars used the ralley gauges and the 72 340 cars used the same gauges as the standard engine cars. There are minor interior differences but I can't think of any specific ones right now other than the 72 Demon possibley having a cardboard headliner vs. the cloth of previous years.