I know you can get the rotors and calipers for stock mopars. but they will probably have to locate them and then ship them to you taking more time. you can go to the parts store and have the part either in stock or sent to the store next day at no extra charge. sure beats waiting a couple days for a part that might be available for a few more years.
I have done the 73-up disc conversion and have had to wait days for parts.