One of the students, while talking with Mr. Escalante outside, is holding a can of Diet Pepsi bearing the logo introduced in 1985, three years later then the movie takes place.
When Lupe is studying and her mother comes home from work, her mom asks her to turn off the lamp that is across the room. She is sleeping directly under a different lamp that doesn't seem to bother her.
In most of the classroom scenes, there are close up pictures of the Planet Uranus along with 2 of its moon (Ariel and Miranda) posted in the back of the classroom. It would have been impossible for those pictures to be hanging in the classroom because the events depicted in the movie took place in 1982. The first time humans had close up pictures of Uranus and its moons was when the Voyager 2 spacecraft flew past Uranus in 1986.
When the students are in the classroom being questioned about cheating you can see Pearson (Rif Hutton) in the background cap his pen twice between shots.
When Kemo returns home after thinking his car is stolen, you see that the front windows have curtains closed in them. Once Angel shows up with his car, Kemo goes to the window to see what is happening and the curtains are wide open.