You are correct, that its a 72 or up. Also the 72s have bumper guards and they incease in size with each passing year to 74. Fed mandated bumpers and Dodge just kept making them bigger and with more rubber
I'd say that the car is a mix of 70 to 74 pieces and some that are just Dodge or Plymouth. Example would be the hub caps and gas cap. Looks to be mostly there from what I can see. Good luck and keep us posted on what you will be doing.