In the 1984 yearbook, there are several anachronisms. There's a clip of A-ha's video for "Take On Me", which wasn't released until 1985. There's a photo of ALF, a video clip of the California raisins, and a photo of four girls with the inscription "walk like an Egyptian". Alf, the California Raisins and the song "Walk Like an Egyptian" are all from 1986. Near the end of the yearbook credits, the phrase "don't worry, be happy" appears with a yellow happy face. "Don't Worry, Be Happy", the Bobby McFerrin song that popularized the phrase, wasn't released until 1988.
When Matt Franklin (Topher Grace) gives his speech before entering the ball, in the crowd is a party-goer wearing an Adidas beanie with the modern 3 sloped bars logo. The film is set in 1988, but the modern Adidas logo wasn't designed until 1990.
Anachronisms: When Barry is fired and gets into Mike's sister's car, as they pull out immediately behind them is a Porsche 928 GTS - this model wasn't available until 1992; the correct model should have been an S4.
The GTS model has a band of red reflector across the rear connecting the light clusters. The S4 (correct car for 1988) has none.
In the beginning of the film when they are at Suncoast Video, the VHS box for the film "Twins" appears on a wall behind Topher Grace. This film takes place in early September 1988 and "Twins" wasn't released theatrically until December 1988. The EARLIEST "Twins" would have been released on home video is summer 1989.
After Matt shows off his impressive math skills, Carlos says that he's "like having Rain Man on the floor, except you can touch him", comparing Matt to Ray Babbitt in the movie "Rain Man". This conversation takes place on Labor Day (September) of 1988, yet "Rain Man" wasn't released until December of 1988.
Tori lists Purple Rain as her favorite album in the yearbook. While the album and movie were both released in 1984 when they graduated high school, they were released on June 25th and July 27th respectively, both of which are dates after when they would have graduated.
People did not lift up dually pickup trucks in the eighties (four wheels in the back, with expanded fenders). It wasn't until the very late eighties when people started lifting up regular four wheel drive pickups.
When Matt and Barry are found in the stolen car (after they run it off the road while trying to snort cocaine) by Matt's father and his police partner, Matt's father breaks the driver's side mirror off the car with his baton. When he lifts Matt off the ground, the mirror is on the ground, but there is what appears to be one still attached to the driver's side of the car; it is actually the head-restraint of the driver's seat that the camera angle makes appear to be a reattached mirror.
In the video store scene at the beginning, as Matt is about to re-enter as a customer, there are two woman walking past. One is wearing jeans, a purple top and holding a red purse, the other is wearing khaki pants and a pink top. They walk by before Matt enters and disappear from the frame. They walk by a second time as he enters the store.
When Anna first informs Matt that she heard back from Cambridge in her room she does so by holding up an envelope that clearly says "Cambridge University" on it with the university's crest below.
The correct name is "University of Cambridge" and would say so on the envelope (with the crest to the left) like this:
XX University of
Besides, she would not receive her notice from the University of Cambridge anyway because you apply to a college within the university and the college responds.
"Japanese takeovers' is the initial lie Matt Franklin tells Tori regarding his job description at a non-existent Goldman Sachs Los Angeles office. When Matt introduces himself at the second party in Beverly Hills to Tori's lecherous boss at Drexel Burnham Pete, his story changes to 'currency speculation'. The supposedly intelligent Tori accepts this new lie with out blinking an eye and even confesses she was impressed with Matt's 'Rainman-like' gift with numbers demonstration.