While examples of racism and racial name-calling are seen, there's no evidence of institutional segregation in food service, accommodations or otherwise.
In the newsreel that opens the movie, Leon Carter's team is identified as the Baltimore Elite ("e-leet") Giants. A team by that name existed, but its name was pronounced "e-light".
When Leon breaks through the lid of the casket, it can be seen that is made of Styrofoam and not of wood or metal.
In the first game played against the white team a kid in the stands holds a 50 star flag. But as the setting is the Great Depression (1930s) the flag should have been a 48 star flag (50 star flag only came into being in 1960).
Right after the team returns to St. Louis Bingo tries to persuade Leon to return to the team. The pipe that Leon is smoking has a plastic mouthpiece on it, which is from about 20 years in the future.
A modern scooter and a modern convertible are visible in the distance during the fight between Bingo and Leon.
When the team returns to St. Louis, they see some kids playing a baseball game. The trees around the kids have Spanish Moss in them. However, Spanish Moss does not grow that far north.