Are 1987 and 1989 Buick Riviera grilles compatible?

I was just given a 1987 Buick Riviera in good running condition because it was declared a salvage vehicle by the insurance company. Apparently, replacing the the grille, hood and some other connector parts was more expensive than totaling the car and paying a check for fair retail value. The person who gave it to me has 2 other vehicles, so he didn't need it anymore anyway. But finding the parts for this car has been a nightmare! I was told that the 1986-1989 Riviera are all the same body style, but then discovered AFTER I bought a used 1989 grille on-line that the 1989 body was somewhat different than the 1986-1988 version. The part hasn't been delivered yet, so I don't know whether I should keep looking. I've looked at some pictures, but can't tell whether the grille between a 1987 and a 1989 is different. Does anyone know?