When Leopold Doppler (Glenn Shadix) is being pelted by the gravy boats, he shouts "Rosebud" from Citizen Kane and "Top of the World, Ma!" from White Heat. However neither of these films were released at the time the movie was supposed to take place, the summer of 1940.
Ralph's father mentions that the "Exposition" is going to open soon. The Century of Progress Exposition, a.k.a. The Chicago World's Fair, opened on May 27, 1933, when Jean Shepherd was 11 years old. The movie takes place in summer, not spring.
The movie mentions the Century of Progress Exposition of 1933 & 1934 as a current event, though the previous movie, "A Christmas Story," is set circa 1939 or 1940. In the gravy boat riot sequence, Leopold Doppler, Manager of the Orpheum Theater, announces that one of the movie-star theme china pieces, "your Sonny Tufts Big Boy platters," already is on the trucks being shipped to the theater. Tufts made his movie debut in 1943 in "So Proudly We Hail!"
When Barkley summons the Bumpus hounds, they run out the front door and fall into mud, because the porch is missing. They are seen crawling out of the mud, with mud all over their legs. In the next shot when they are chasing Barkley, there is not a trace of mud on them.
In the gravy boat riot sequence, Orpheum Theater Manager Leopold Doppler announces that part of the movie bill is a documentary on the exports of Kuala Lumpur. Kuala Lumpur is a city, not a country; it was the capital of the British colony of Malaya (now known as Malayasia). The major trading port in the region was Singapore.