At the theatrical opening of this film, kids were handed (for free) an "autographed" picture of Rhubarb. The signature on the photo was a paw print.
The book, "Rhubarb" was published in 1946. In it, Yeager takes his boss, Banner to the movies, to a "domestic comedy". Banner doesn't like the leading man, because he saw him play a drunk in another movie. Clearly they are referring to Ray Milland, in "The Lost Weekend", 1945. Five years later, Ray Milland played Yeager in "Rhubarb", 1951.
Fourteen different cats portrayed Rhubarb at different points in the film. Each cat was trained to do a different trick. Three of the most identical cats appeared in the courtroom scene where Polly Sickles has to choose which one is the real Rhubarb.