Continuity mistake: When Sidney is talking to the killer in the police station, her phone has a "Nokia" sticker on the bottom of it. Later in the scene, it's gone. (01:29:15)
Continuity mistake: When the killer and Sidney are locked in the screen room together and the killer slits the movie producer's throat, if you watch closely when he's talking to Sidney and waving the knife around that in the first shot there's blood on the knife and then it goes to Sidney and back on the killer and when it cuts back there is no blood on the knife. It then again goes back to Sidney, then back to the killer and the blood has magically reappeared on the knife. (01:36:00)
Continuity mistake: At the end of the movie, after Dewey asks Gale to marry him, she lays one on Dewey. She leans to the left of his face when they start kissing, and at a cut away long shot she suddenly is kissing on the right... then the close up is back at the left. (01:44:30)
Continuity mistake: When Sidney is first going into the house for the end of the movie it is clear that she is not wearing the vest underneath her clothes and as she is walking around or when she is rolling on the ground fighting with her half brother you see her bellybutton but then she has the vest on and it goes over the belly button.
Continuity mistake: When Sidney is fighting the killer, when ever a big stunt comes up, the killer's hair gets lighter.
Continuity mistake: Gale and the killer go flying through the basement door, you see the door opens out, but when they crash through it, it opens in. Its not a two way swinging door, because you see the hinge at the top of the door to open it out, not in.
Continuity mistake: In Scream 2 Dewey walks with a limp and his right arm curled up. In Scream 3 he walks with a limp and his left arm curled up.
Continuity mistake: The ice pick remains free of blood even when Sid has stabbed the killer with it twice.
Continuity mistake: Gale's bangs change lengths throughout the film.
Continuity mistake: In the scene where Jennifer gets killed and falls through the mirror look at Dewey's hair it's all messed up, but in the scene right after that when Dewey and Gale are looking for Tyson his hair's all combed back again.
Continuity mistake: Dewey rolls down a hill after shooting at the killer. The cut on his forehead changes shape from circular to two parallel lines then to a straight line and a waved one.
Continuity mistake: Roman's sideburns change lengths towards the end of the movie.
Continuity mistake: At the end of the movie when Sidney is lying on the floor, Roman is pointing the gun to her head about to kill her. The gun is clearly pointing to her head/neck area when he shoots, but Sidney still lives and shows him she was wearing the vest. The vest protects her chest and Roman shot her in the head.
Answer: Not expressly, though it could have been the date of some significant event (December of 1988) but someone as security-conscious as Sydney now is wouldn't be stupid enough to have her code be something that could be guessed.