Not an urban legend

Rico says the whole "Lee Marvin talks about fellow-Marine Captain Kangaroo on Johnny Carson" thing was a myth, apparently, but there's another "Lee Marvin on Johnny Carson" incident that Rico saw personally (as a much younger man staying up late while working for his uncle in Florida, circa 1967), and therefore knows it happened, even if the Internet doesn't seem to...

Marvin, probably drunk (as he was known to be at the best of times), sat on the couch and said not a word for what seemed like forever, as Carson struggled to come up with a question that Marvin would answer. Finally, in desperation, Carson asked him about his service in the Marines during the war. At this, Marvin bestirred himself, but only to say: "Who the fuck cares?" They went to a commercial and, when they came back, Marvin was gone.

Rico says he had to fake the photo of the two of them, because none exists that he can find...