The home video versions of some episodes have changed music in some scenes. For instance, when they sing "Happy Birthday" at a birthday and when 'Leslie Nielsen' sings Judy Garland tunes in the nightclub. Presumably this is due to a music licensing issue.
When initially broadcast, the first episode included a scene with Drebin walking past a homemade banner saying "Hello to Howard, Frank, and Dandy Don" - a la Monday Night Football, another ABC program. The banner is not on the video or syndicated versions.