Back in the 60s the USIA (United States Information Agency) conducted a survey in several dozen countries to try to discover what was the most recognizable image of the United States. Actually there were two; an Indian and a Cowboy. So, I think it would be reasonable to say that dressing like a cowboy would mark you out as an American, while dressing like an Indian (unless you are one) would mark you out as a Ward Churchill wannabe.