I saw that one a long time ago and have no recollection of how authentic it tried to be.
@GabrielsLamb, I’m afraid your first link doesn’t appear to go to anything involving the movie Sexy Beast, which in any case is a heist movie that doesn’t have anything to do with Native Americans. Did you give it the wrong label?
@jeruba That was in reference to the protagonist in the film. He played the part of the lead Indian. It is an older film from 1973 It’s called Winterhawk but they don’t have a better link on youtube concerning it so that was the best I could do.
@Leanne1986 A writing professor recommend that one to me, but I haven’t gotten to it yet. It kinda surprised me because because it was so maligned when it came out and he was dead certain I would love it. Maybe it missed it’s market?