I discovered something about the PD status of Columbia cartoons
I discovered that a certain cartoon series that ran from 1930 to 1931 that was made by Screen Gems didn't have its copyright renewed. I'm talking about Toby the Pup. I discovered that his first film, The Museum, didn't have it's copyright renewed while searching through the 1958 copyright film renewals in the catalog. Wikipedia says that the majority of his films aren't renewed. I guess I answered my own question if any of the Columbia films are public domain.