Corrected entry: At the credits, the fictional character is mentioned: "Tuttle.........as himself" (00:25:05)
Corrected entry: When Margaret and Frank look over Tuttle's file, Margaret reads aloud the words "Berlinishes Polytechnikum". The correct German wording would be "Berliner Polytechnikum". While this could be ascribed to a mistake of Hawkeye or Trapper, no indication of that being the case is given in the show.
Correction: It is indicated. That is what Hawkeye says as he writes it down. He doesn't know German well.
Correction: This is a joke and not a mistake. By "fictional character", you do not mean one created by MASH writers for the show, but a fake Captain made up by Hawkeye and Trapper. It was just a funny way of saying since Tuttle only existed on paper, that paper existence was real and fictional.
Bishop73