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: Based on the films being shown at the theater, the movie appears to be set in 1981. One of the TV commercials shows the Energizer Bunny, which didn't make its first appearance until 1988.
Factual error: Opening the blank envelope, Marta finds the fragment of the toxicology report. It is signed "Office of the chief medical examiner, Norfolk County, Massachusetts." But then it writes also the address of said office, which is in Marlborough. Marlborough is also the city when Marta resides, and where the lawyers' letters we see come from. But Marlborough is also a city in the Middlesex county, not Norfolk. (01:28:25)
Factual error: A plastic bucket is seen. Plastic buckets were invented in the 60s. (00:50:05)
Suggested correction: There's no plastic bucket seen. If you're referring to the bucket cops are using at the crime, there's a shot of the bucket on its side and you can tell there's a metal bottom.
Factual error: Alec Baldwin opens a pack of Chesterfield cigarettes and they have a filter. This is in the late 50's - Chesterfields did not have filters until 1966.
Factual error: As well as the sergeant's stripes on his cuff, Sergeant O'Neil wears three pips on his epaulettes, which would indicate a much more senior rank and would not be worn together with the stripes.
Factual error: In 1940 3 of Alf White's men are arrested. As they are taken out of the pub they were in Alf and his son stand in the doorway. To their left (viewer's right) are posters for Floyd Patterson (who would have been aged 4 or 5 at the time) and the Platters (formed in 1952) and Lonnie Donegan (started performing 1949). (00:20:03)
Factual error: Mohegan Sun casino is in the state of Connecticut. Connecticut does not have legalized sports betting and did not have it in 2012, when the film is set, therefore Julia would not have been able to place Howard's bet.
Factual error: During the FBI briefing, the coordinates of the mosque supposedly in Harlem are shown on screen long enough to allow you to read them. The coordinates are 34.1234379 -117.177613, which would put the mosque somewhere in California. (00:09:45)
Factual error: It's a hard winter everywhere is film except in the scenes that take place in Denver. In one scene when Coxman kidnaps Viking's son, there are full leaves on trees and cherry blossoms. Moments prior there's a frozen tundra shot coming into Denver.