Early in the movie, the black car driven by the detectives is a Plymouth. Then it is a Dodge. Then it is a Plymouth again.
A Princess phone is seen on a side table in Julia's apartment. The setting is 1957, but the Princess telephone was not introduced by the Bell System until 1959.
When Moses Randolph exits the pool (at around the 22nd-minute mark) his hair is wet. Just two seconds later (change of the shot) his hair is clearly dry.
When Lionel and Laura are in bed together and she starts to cry, she puts her hand to her face with her fingers flat. Then, in the wide shot, her fingers are bunched together. Then back to flat again in the close up.
The same green Studebaker Lark is parked on the street in at least 4 different locations.
Moses Randolph is shown pulling out a pack of Chesterfields (an unfiltered cigarette) and removing a smoke. However, the next scene and other subsequent scenes show him smoking filtered cigarettes instead.
Thelonious Monk's most famous composition is entitled 'ROUND MIDNIGHT. The album by the Miles Davis Quintet from 1956 is entitled 'ROUND ABOUT MIDNIGHT with a wrongly set single quotation mark. The end credits are listing 'ROUND ABOUT MIDNIGHT, performed by Babs Gonzales.
When Lionel is driving Laura home the steering wheel never moves as he drives, indicating that the vehicle is being towed and not driven.
When Lionel drives up to the club with Laura in the '57 Chevy and they are seen walking inside, you see that Lionel has left the car's lights on.
During the car chase early in the film, the car carrying Lionel and being driven by Gilbert runs over the sidewalk as it rounds a corner, clearly showing the curb ramps for the handicapped, that would not have been installed until after the Americans with Disabilities Act of 1990.
At the beginning of the film when the two were sitting in the car listening to the conversation from upstairs, you hear an electronic siren in the background. They were not invented until 1964. A few moments later, you see a NYPD patrol car race by with its red light turning. It should have had red and white alternating lights but the siren was correct for the period then.
The style of panic bar on the exit door in the auditorium at the public meeting was not invented until 1988 by Thomas Industries.
The term "granny glasses" did not exist in 1957.
Laura describes the racist policies by referring to "Latino" families, a term that would not become widely used until much later in the century, particularly outside of the western United States.
When Lionel enters the club at night to find a dead body, we can see two crew members and boom mics on the left side.
At around 2:02:02 a mystery man in the subway train turns to follow Laura as she walks by. The cameraman is then clearly shown reflected in the window and is seen turning to follow the action.
Around the 2:04:30 mark, with Giant man (Radu Spinghel) hanging by his fingertips from a window ledge, Laura throws a pot plant at his head. As he falls to the ground you can clearly see the wires attached to his safety harness on the right of screen.