A gentleman wearing his hat at the dinner table, with ladies present, was considered rude and disrespectful, in the era of this story, and was not permitted in restaurants.
When Tom is walking towards the Pacific Ocean, his pants are wet a couple of inches above his shoes though he has not yet gone to the water's edge.
The story is set in New York with numerous flags shown flying but all railroad shots are of British locomotives and carriages (coaches) where the film was made.
In the closing credits, Johns Hopkins Hospital is misspelled "John Hopkins Hospital".
The letter in the film from Wolfe to Perkins is somewhat different than the actual letter, ie..."Fourth of July" changed to "November."
After the 1929 success of Wolfe's first novel "Look Homeward, Angel," Max Perkins takes him out to dinner at a fancy New York restaurant to celebrate. Wolfe and the others at his table are shown drinking martinis in celebration. Since Prohibition in he USA was still in full effect in 1929, the serving of alcohol in that upscale establishment, which was clearly not a speakeasy, would have been strictly illegal.
Maxwell Perkins tells Thomas Wolfe his book needs a new title that will appeal to potential purchasers, and gives the example of F. Scott Fitzgerald changing the title of a novel from "Trimalchio in West Egg" to "The Great Gatsby." The real Perkins, as Fitzgerald's editor, certainly would have known that "The Great Gatsby" was a flop upon its release in 1925 and did not sell well until the 1950s.