Just inside the main entrance is the lobby used for filming. Above is a still from the film; below in 2014.
If you go through the lobby and turn right down the first hallway, that is the hallway used for the girls' dressing room in the film. Above is a still from the movie and below is the same spot in 2014.
The auditorium is also in this school, as seen in the above still. A Central Middle School employee saw me walking around and taking photos and threw me off property. She wouldn't even let me see the auditorium but I did get her to admit their auditorium was used for the film.