67 new yorker cop car?

Hi what are some tell tell signs to look for to see if my new yorker was a cop car, there is a few strange things on my new yorker like the newport front and rear corner extensions and i just had my brakes done and brought new everything (the self adjusting cable and clips etc) and the guy who done them gave them back to me said i didnt need them as they are not the self adjusting brakes, and in my manual it said only the cop cars didnt have self adjusting brakes?
Author: peterlucas