Post up a pic. I was thinking you had a 81 Indy Pace Car replica but it doesn't have the Hawk decals. Maybe you have a one off. Here's a pic of a 81 Pace Car replica. But than the 4.1 didn't come out until the 82 model year. The 8th character of the VIN should have the number "4" if it's a 4.1.
Buick also had a wild sport option back in 78-81 which included two-tone paint and some Hawk decals on the front fenders. It was available on all models of the Regal and Century. If you checked off the right box on the order form you could have factory painted bumpers on a Century. My particular favorite was the Century Sport Wagon. It had the same front header panel as the Century Turbo Coupe. I've never seen one in the flesh. Only in pictures.