I remember when they incorporated the original 'Abe Vigoda is dead' rumor into an episode of Barney Miller. Fish is reported dead and has no luck convincing the NYPD he's, in fact, still alive. A great moment in the episode is when a prisoner remarks to Fish "You look just like Boris Karloff!" and Fish replies "We have a lot in common. We're both dead."
The 'Fish is Dead' episode preceded the People Magazine article error by several years; though it probably gave juice to the error and subsequent rumors about his death...uh...premature death.
Does anybody recall if in the 'Fish is Dead' episode, or perhaps another, if there is a scene where Fish is dozing at his desk and someone mistakes him for being dead?