Coincidence, most likely, but cool, I don't think Fistful would have influenced it it would have been highly unlikely
Check out "A Man Called Shenandoah's" (1965-66) Robert Horton's cool snowbound title sequence here, his bear skin is reminiscent of both the Man With No Name's pancho & John McCabe in "McCabe & Mrs. Miller" and scenes from "The Great Silence":
http://www.youtube.com/watch?v=WvAuSwXmt-k&feature=related