Bumper bracket questions
1973 Dart Sports had standard brackets front & rear. '72 & earlier brackets & bumpers are different - (i.e.: Demon - straight bumper) Most 1974 Dart Sports had standard front brackets too. 1974 was a "transitional" year so results may vary.
1973 & earlier take the same brackets & bumpers. '73 would have jack slots if you want to stay "correct".
You probably noticed that later bumpers with the "shock brackets" have 2 extra carriage bolts near the top of the license plate area and4 of the others are relocated.