Factual error: Towards the middle of the film,Pacino and Depp are walking downtown, there is alot of traffic and some of the cars are "post 1978" model . One in particular caught my eye, which was a mid-80's Ford Taurus (even the model of the car didn't exist in 1978).
Factual error: When Johnny Depp and Al Pacino are driving in the car (I believe it's the first time Depp drives Pacino around), they pass an MCI billboard - the one that continually updates the figures as to how much money you'd save if you had MCI long distance phone service. MCI didn't exist in 1978.
Factual error: A group of guys are walking into a hangar at some airport. When they are walking into the door you can see a jet moving behind them. It is a Continental Airlines jet with their new Continental logo on the tail. I believe they updated it in the last two years. The movie was set in 1978 and this logo obviously wasn't on the jets back then.
Factual error: When Depp makes a phone call to his wife on a pay phone, the price of the phone call - $.25 - seen on the phone. Phone calls didn't cost that much in 1978.
Factual error: In the airport scene, the Burlington Air Express plane being towed is marked Burlington Northern Air Freight, Inc. (BNAFI), a subsidiary of Burlington Northern Railroad. In 1982, BNAFI was acquired by the Pittston Company, which later became Brink's. In 1986, BNAFI changed its name to Burlington Air Express, which is outside of the movie's time frame of 1976-1982.
Factual error: Toward the beginning of the movie, the boss of the family at the time, Carmine Galante, is shown getting out of a car as the crew watches in awe. Soon afterward it is learned that he was murdered and Leftie is seen in Donnie's car holding a newspaper with Galante's famous post-mortem photo, cigar in mouth, on the cover. Later in the chronology of the movie's events, when the crew is poolside in Florida, Sonny Black is holding a newspaper with a cover story that John Wayne has died and he asks, rhetorically, "How can John Wayne die?" The problem is that the movie's chronology is way off. John Wayne died on June 11 1979, a full month before Carmine Galante was murdered in a Brooklyn restaurant on July 12 of that year.
Factual error: In the beginning of the movie when Lefty asks Donnie if he is Don the Jeweler, Donnie turns to the man behind the bar. On the bar shelf there is a bottle of Absolut Vodka. The movie was set in 1978, and Absolut Vodka was first launched in 1979. The design of the actual bottle in the scene was launched even later. (00:06:20)
Factual error: In the scene where Depp visits Pacino at home during Christmas, Pacino is watching TV. On Pacino's TV stand are VHS tapes, including some movies that where not made until after 1978, when this film is set: Death Wish 2, After The Fall Of New York, House, Low Blow, Ghoulies and The Last Dragon.