In the beginning, three years after the opening shooting, when a group of guys are at the bar, one comments on how Dolly Parton was on Johnny Carson last night. Dolly Parton didn't appear on the Tonight Show in the 1980s until 1986.
In the opening scene when Sean Sullivan shots the three guys in the bathroom you hear 3 gunshots (there is no visual of the event here). At time index 1:12:18, Sean Sullivan goes to the bathroom and shots the three guys, you hear four gunshots