Since Mickey's Christmas Carol was released along with a re-issue of "The Rescuers", The Prince and the Pauper was released with the sequel "The Rescuers Down Under." That sounds funny to me. I also wondered why this very short was not listed in an official theatrically Disney animation filmography.
Like Mickey's Christmas Carol, The Prince and the Pauper is a cartoon you'll enjoy again and again. It's recommended.