For a game that is self-purported as a realistic interpretation of '47 Los Angeles, it's kind of odd there would be so many errors. The game designers have certainly Shown Their Work, but the Rule of Cool (and maybe a few Acceptable Breaks from Reality) made for a few cases of A Spot Of Weak Anachronism Broth On The Side.
- The fact that no one seems to care about wearing gloves to handle evidence and there is practically zero mention of fingerprinting makes the policing of the period seem rather more archaic then it actually was. The first use of fingerprint evidence to obtain a conviction was in 1902 in France, by 1906 the New York Police Department had introduced the fingerprinting concept into the United States. Even if it wasn't as perfect, understood, nor useful as it is nowadays, detectives in 1940s Los Angeles would have still been reprimanded to hell and back for touching any piece of evidence with their bare hands, and mandatory sweeps for any convenient fingerprint evidence was a go to by that time.
- This is made more confusing by the fact that characters do mention swiping for fingerprints, particularly on the Black Dahlia letters—–mentioning the letters being swabbed with gasoline means they can’t find prints. It makes the handling of precious evidence and fresh cadavers with Phelps’ bare hands all the more perplexing.
- When a massive explosion, complete with a mushroom cloud, occurs in Downtown L.A, Biggs at first wonders if the Soviets have dropped the H-Bomb on Los Angeles. Although the idea existed by 1947, serious development into hydrogen bombs did not occur until the early 50's. The first full-scale thermonuclear test was by the United States in 1952, while the Soviets wouldn't do so until 1955. It's likely the devs confused the H-bomb with the A-bomb, which was much more well-known at the time, but even still the Soviets wouldn't test one of their own until 1949.
- One of the main collectables, the golden film reels, are named after real life movies. The game takes place in 1947. Many of the films found are released after this date.
- The designers put the Intolerance set in the game, which was demolished in 1919. Although this was admittedly intentional, as the creators stated they put it in for a bit of cinematic fun during the conclusion of one of the cases.
- Another minor example: LA's famous palm trees would have only been at about head height in 1947. The developers intentionally made them taller because they thought it looked cooler.
- Many of the vehicles and songs in the game are from 1948 or 1949, the most notable being the 1949 Chevrolet Styleline, although next-model year vehicles are generally available for purchase partway through the current model year.
- All the cars in the game have brake lights, a feature that wasn't commercially available until 1952. This is more of a gameplay choice to show if a car is moving or stopped.
- The jazz pieces from the game's original score are done in a style that wasn't created until the mid-50s, but they just set the mood so well.
- Also, the term "motherfucker" is used a few times, even though the term was not notably used until the late '50s.
- On the other hand, the term "mother fucker" - that is, two words, not one - dates back at least to the late 19th century.
- In one case, there is a letter with a ZIP Code on it. While addresses in large cities gained Zone Codes like Chicago 6 or Los Angeles 19 starting in 1943, ZIP Codes were not introduced until 1963.
- In one of the Vice cases, gangster Bugsy Siegel is mentioned as if he was still alive, when in reality he was murdered on June 20, 1947, months before the Vice cases take place.
- Many of the new houses going up are built with plywood sheeting for the walls. While plywood did exist back then, it was very expensive and used almost exclusively for boats and furniture, simple boards being the more practical option in housing construction. Production of plywood has gotten better since then, resulting in it being cheaper than boards (and thus a more common construction material) today.
- The KTI Radio announcer says that the station is on 760 kilohertz. The reciprocal second wasn't called hertz until the SI was adopted in 1960. Before that if would have been called kilocycles.
- K rails are used to delineate the playable areas. K rails were not developed until the 1950s.
- Tickets for a flight on Trans World Airlines are shown. While TWA did exist in 1947, it was known as "Transcontinental and Western Airlines" at that time. The re-branding to "Trans World" wouldn't happen until 1950.
- The USS Indiana is stated to have been scrapped. She was placed in mothballs in September 1947 with the rest of the South Dakota class and had several attempts at modernization (including replacing the main guns with missile launchers), but wasn't scrapped until 1963.
- In "Armed and Dangerous", the narrator uses the phrase "a one-way ticket to Palookaville" in his narration. This phrase is a quote from the 1954 film On the Waterfront, despite the fact that L.A. Noire is set in 1947.
- Whenever Phelps or Kelso are making phone calls, they have to be connected by a switchboard operator. In a city as large as Los Angeles, dial service would've been introduced long before and unless one was making a long distance call, operator assistance would not be necessary.
