Factual error: One of the main characters has a Harley Davidson. The movie is supposed to take place in the fifties. The Harley had an electric start primary cover which wasn't made by Harley until 1965.
Factual error: Right after George Wilson kills himself with the revolver, the gun is seen falling into the fish pond in Gatsby's living room. Since Wilson shot himself in the head by placing the gun to the roof of his mouth, there is no possible way the gun could have flown so far away from his body, especially without getting bloody.
Factual error: The movie events take place in 1957, but in a poster at the reception is written Die Zauberflote, November 20 1960. (00:06:55)