In fact, Robb, if my own experience is typical, 12 years of US public school didn't teach us a damn thing about Native Americans, least of all details of the differences in culture and costume between various tribes. What we knew about "Indians" came primarily from TV westerns and reruns of old western movies. In the regions where I attended elementary school (California, Alabama, Washington) Native Americans were mostly ignored except as supporting characters (usually antagonists) in stories about the conquest of the West. We'd heard of the Apaches and the Navajos, and occasionally someone would mention the Iroquois or the Cheyenne. To most of us, though, Indians comprised a vague, monolithic group whose role in history was primarily to demarcate episodes in the European experience. Which headdress was appropriate to a scene and who did and didn't wear feathers was esoteric knowledge. I'm sure some kids were history buffs enough to research such things, but they'd have had to do it on their own time outside school. I didn't know anyone like that personally.
Looking back it amazes me how ignorant we kids were of Native American history. Even African Americans got more "screen time" in history classes, though of course what we learned was--especially in the South--a very sanitized version of the facts. For the most part Native American history and culture were relegated to footnotes and a paragraph or two.