nope, it's definately a lebaron. They only made this bodystyle for a coupleyears. before that there was also a lebaron in a style similiar to the 77-79 diplomats, in 1980 they got a restyle. The le-barons had chrysler style split front grilles and a totally diff. tailight setup than the diplomats.
Yes, you are correct. I could tell right from the beginning. By the way, I would assume that they only used them in 1981 as that was the only year the M-Body LeBaron was offered as a police-package car.