Factual error: While handling the ignition coil cable to the distributor cap, Joe Pesci tells De Niro that the timing chain needs adjustment in his truck. A truck of that year with an inline Chevy motor would not have a timing chain at all, instead this truck would be equipped with a direct drive timing gear. Even if it had a timing chain, it would be behind the water pump and a cover. It would have been a several hour job to replace, not possible to adjust it.
Factual error: The interior shots of the Gemini and Apollo Spacecraft show worn and dirty panels, knobs, switches and circuit breakers. The movie most likely used some original cockpit trainers, but in reality the astronauts were flying brand new spacecraft that were spotless.
Factual error: In a scene in 1980, Brian May is teaching everyone the beat for his new song "We Will Rock You." However that song was released in 1977.
Factual error: Robert McNamara is wearing a multi colored Polo shirt talking to Mrs. Graham in 1971. The Ralph Lauren Company did not make the shirts until 1972.
Factual error: In the scene where the Navy Seals are riding in the cars, the VA state vehicle inspection can be read from behind. It read "6 13" for June 2013. This would have been correct for the period the film was made, but not for the time of the incident.
Factual error: It's late 18th, possibly early 19th century and, as Jane and her sister walk along the beach, a construction crane is visible on the horizon.
Factual error: When Mark types email addresses in to tell people about facemash, he writes to several people @harvard.edu. At the time the movie takes place, undergraduate email addresses were all of the form email@example.com. Furthermore, the network brought down by facemash would have been referred to as the FAS network. (FAS stands for Faculty of Arts and Sciences; the eponymous network covered all buildings within the College and Graduate School of Arts and Sciences.).
Factual error: When Suzanna and Lisa are at Daisy's house, Daisy lays out money for Lisa so that she can get pancakes, and the bill she laid down is one of the new bills. This movie is set in the 60s so of course they wouldn't have the new bills, considering they didn't start making them until 1998.
Factual error: The Map of Europe used for plotting their route displays the Netherlands incorrectly, showing its two major central polders (low-lying reclaimed landmasses surrounded by dikes) which weren't drained and finally completed until 1968.
Factual error: In the assault on Fort Wagner, the regiment attacks the fort from the wrong side. In reality, the troops attacked from the south.
Factual error: When Christina mixes a drink for one of Mommie's "guests" she bends down behind the bar to put a bottle back. Sitting on top of the bar is a Trigger Sprayer bottle of "Fantastick" - a spray that did not come out until the late 60's.