Just read the interview Mr Costner gave to the "Spiegel"-magazine when in Berlin. At one point they asked about the chocolate-eating-scene and said that JW probably would have been disgusted of how cowboys were portrayed. Costner's answer (I'm trying to translate his answer, printed in German, back to English):
"John Wayne did a lot of stupid things. I don't think that he made all that many good movies. And there aren't that many good westerns. I have maybe seen ten that I like. I hate it when westerns take the short-cut to the showdown."