SEMENKO: I have come to pander to the tastes of the tasteless.
COACH: Oh, you want to head the food committee! Wait a minute!
COACH: We got our chairman for the food committee!
CLIFF: Hey, I like my buffalo sunny-side up there, chief.
SEMENKO: You're referring to my apparel?
CLIFF: Oh, hey, uh, no offense there, little beaver, but it is a tad, uh, a tad out of the mundane, you know?
COACH: Excuse me, sir, but w-what is that outfit?
SEMENKO: This is an Arapaho ceremonial tunic worn by the village elders when they hold council in their hunting lodge.
SEMENKO: I earned it by letting them pierce my flesh with wild turkey quills.
Of course, the shirt is probably a bunch of hooey. It looks like a cheap knockoff made specifically for the show. I've never heard of a special tunic worn in a tribal council or given to someone for participating in a Sun Dance. If it were that special, would Semenko wear it in a bar, where anyone could spill something on it?
It's an odd choice of apparel to demonstrate Semenko's personality. Yes, he's an intellectual elitist who disdains the unwashed masses, but it's not clear he's a multiculturalist or even a liberal. Wearing an Arapaho tunic in downtown Boston makes no more sense for him than it would for Frasier.
The bar's wooden Indian
Also worth noting is the wooden Indian to the right of the bar's entrance. It's a typical Indian "brave" with his arms folded and a vest or cloak around his shoulders. This "Indian" appears constantly--every time the camera pans to the near end of the bar. If you think about it, the statue may vie with Tonto as the most filmed Indian in TV history.
I doubt you'll ever learn anything about real Indians, such as their participation on both sides of the Revolutionary War, in Cheers. Like many Indian monuments, the wooden Indian is a mixed blessing at best. It reminds you of the Indians' existence, but it implies they existed in the past.
For more on the subject, see TV Shows Featuring Indians.