In her 1995 memoir "After All," Mary Tyler Moore says that this special was originally going to be titled, "Mary Tyler Moore Explains the History of the World."
"Mary's Incredible Dream" was, as some industry people call it, a true "one-shot wonder." That is, this special *hasn't* been rerun and/or syndicated since its initial airing on Thursday, January 22, 1976 at 10:00 P.M. Eastern on CBS.