My friend has a 99 bonneville and the dashboard was stolen with her stero(why they stole the dash beats me), but the Jy has a 96-97, will it fit?

Junk yards normally have interchangeability manuals which should tell them if it will fit or not. In any case, according to Consumer Guide Auto, there were virtually no changes in the Bonneville from 1996 to 1999. So, it probably will fit. Maybe.
Keith
1994 Bonneville SSEi