Factual error: The car Flounder drives is a 1964 model, built beginning late in 1963, but the events of the movie take place in 1962. (00:45:40 - 01:08:25)
Factual error: At Professor Jennings' place, the stoned Boon and Katy sing "Hey Paula." The song was only pressed in November 1962 and didn't break into the charts nationally until late December of that year, whereas the scene depicted takes place sometime in the autumn of the same year, before the song would've even been recorded.
Factual error: In the scene where Pinto buys/shoplifts food from the grocery store and meets the Mayor's daughter, the cash register has an LCD display. A little too futuristic for a flick set in '62. (00:47:30)
Factual error: Boon is using a payphone and behind him, at the left of the screen is the front end of a 'coffin-nosed' 1974-78 AMC Matador sedan, a car built a dozen-plus years after the events of the film. (01:18:10)
Factual error: When Karen Allen is in the kitchen she passes a fridge that has a Bicentennial sticker on it. The movie was set in 1962 and the Bicentennial didn't happen until 1976. (01:21:40)
Factual error: When Larry and Kent first arrive at Delta house, and again after the new pledges are accepted, the Kingsmen version of "Louie Louie" is heard playing. This version was not recorded until April 1963, but the movie takes place in the autumn of 1962.
Factual error: After trying unsuccessfully to call Katie at the all-night cafe, Boone questions where she could be at six in the morning. The scene occurs during broad daylight. If the time were accurate, this could not be so, since it occurred in November. (01:18:30)
Factual error: Bluto crushes a beer can against his forehead. Steel cans are too strong to crush like that. Aluminium cans weren't introduced until approximately 1965, although the movie was set in 1962. http://www.cancentral.com/brochure/historyTimeline_f.htm. (00:07:55 - 01:20:20)
Suggested correction: Maybe it's a joke about his thick skull/him being impervious to pain due to his stupidity/drunkenness? We also see him break bottles against his head with similar indifference and abandon.
Factual error: The bottle of Jack Daniels that Bluto chugs has an aluminum twist-off cap - a convenience not yet available in 1962.
Factual error: The Coca-Cola sign on the pop dispenser in the cafeteria has the "Dynamic Ribbon" device as part of the Coca-Cola trademark. The movie is set in 1962. Coca-Cola didn't start using the Dynamic Ribbon on its trademark until 1970.
Factual error: Listen to the crickets chirping at the football field where Larry and the Mayor's daughter make love. It's fall, everyone has jackets on. It's much too cold for crickets to chirp that rapidly. (Or at all at that time of year). (01:32:00)
Factual error: Mrs. Wormer confuses the meanings of "sensual" and "sensuous". Sensuous merely means appealing to the senses; sensual has sexual connotations. In other words, vegetables are sensuous; people are sensual. (00:46:45)
Factual error: In the scene where Larry and the Mayor's daughter are on the football field, it appears to be artificial turf. Artificial turf wasn't invented until 1965, 3 years after the movie was to have taken place. (01:32:00)
Factual error: At the end of the movie when the riot is taking place, Niedermeyer takes out a bullet and fires upon Flounder from maybe ten feet away and misses - all the bullet does is shatter the seltzer bottle and nothing else. Whether Niedermeyer meant to miss Flounder or not, the bullet would have shattered the bottle with little or no deformation to the bullet itself and would have hit the pedestrian running behind Flounder.
Factual error: In the scene with the disciplinary meeting, the chalkboard says "Pan-Hellenic Disciplinary Council." National Pan-Hellenic Council is the governing body for sororities, not fraternities. Fraternity disciplinary hearings would be handled by either the Inter-Fraternity Council (IFC), or the school's Office of Student Conduct, in conjunction with the Director of Greek Affairs. Further to this error is that the rest of the chalkboard writing pertains to the meeting being held at that time, and Greg Marmalard calls the meeting of the "Disciplinary Council" to order. (01:01:25)
Suggested correction: Although correct the National Pan-Hellenic Council wouldn't be involved - it actually represents African American fraternities and sororities.
Suggested correction: Depending whether or not daylight savings time has ended at that point. If it has and the clocks are an hour earlier now, then it would be brighter by 6 a.m. then if they had not yet. There's no sun in the scene so this could explain it as a possibility.