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68/ 69 coronet body many parts interchange, some may not be exact as there were minor changes but the parts will still work, like the doors, 68 is slightly different than 69 but they will work. Doors from a 68-70 Plymouth B body will also work on your Coronet, but not Charger doors the outer skin is different.
Glass in the same, though there is a difference between coupe and hardtop, and obviously 4 door and convertible.
As far as sheet metal goes things between 68 and 69 Coronet can be made to work , but the extra work involved you might as well stick to 69 sheet metal , like fenders and quarters . The hood will interchange, 69 has a piece added to the front lip for the grille change. Trunk lids and tail panels are not the same. Bumpers are the same 68/69 Coronet.
Outer sheet metal/bumpers/trim on 68-69 Plymouth is different, many interior parts will interchange between Plymouth and Dodge, seat patterns/door panels are different though.
