Character mistake: As Eddie Haskell and Lumpy Rutherford return from the washroom to Mr. Gannon's history class, Mr. Gannon calls Eddie "Louis."
Character mistake: Bret fires at "John Wesley Hardin" four times, but the doctor and all the witnesses say there were three shots.
The Case of the Wandering Widow - S4-E6
Character mistake: As Mr. Morgan (Dean Harens) is being examined by the prosecutor he's also sitting in the gallery.