By the "9" on Officer Dean's uniform, he is working out of the New York Police Department's 9th Precinct, which covers the East Village neighborhood of Manhattan in New York City - which is the area in which this production was filmed.
Tom's car is a 1956 Mercury Montclair convertible. In excellent condition, an example of this vehicle could be worth over $80,000 in 2021.
Officer Dean drives a 1954 Chevrolet Bel Air convertible. In excellent condition, an example of this car could be worth over $45,000 in 2021.
The fact that Marilee Earle is "introduced" is true and not true. She had been in a movie the previous year, Hot Cars (1956), but most of her scene was cut. All that can be made out is a wide shot of her looking at a car; her face is hardly recognizable (unless you know who to look for). So this is, in fact, the first time audiences would actually see her.