Having just watched this episode, I felt compelled to comment on it -- and on the reviews of it here on IMDb.
Yes, this is a re-telling of Treasure of the Sierra Madre. So what? I don't know about the other reviewers, but even when I was young I was often aware that certain episodes of TV series I was watching were re-tellings of classic stories. One that stands out in my mind was the time Richard Basehart's Admiral Nelson of Voyage to the Bottom of the Sea found himself in a re- telling of MOBY DICK, made even more intriguing by the fact that he played Ishmael in the original film version.
It was actually fun to see my favorite characters placed into those stories, and it was fun in this case as well. One never for a moment watches this episode and thinks Edward Andrews is trying to play Eugene Dobbs or that Rod Taylor is trying to play Curtin. And it is laughable to think Cheyenne Bodie has anything to do with Walter Huston's portrayal of the prospector Howard. The film of TOTSM was an instant classic, and a TV homage to it from the studio that produced the film is nothing to apologize for (I was amused by the poster who pointed out any idea of this TV episode "stealing" the plot from TOTSM would logically conclude with "Warner Bros. suing Warner Bros.")
I think was a well-done retelling of the story, with excellent performances from the three leads (once you extricate yourself from some foolish need to compare the performances to Bogart, Holt and Huston), and covers some territory the original didn't in terms of the racism against Native Americans. Particularly like how when Cheyenne (the brunt of some of the racism himself) is attacked for wanting to spend time with some "Injuns" in order to help them, comments along the lines of "Well, after spending some time with white people, it sounds like a pretty good idea".
As for the meaning of the title "The Argonauts", the answer is pretty self-evident. What were the Argonauts going in search of? And if you say "some sheep's fur", maybe there's another classic story you might need to revisit.