Over on my website, I've got an article about the first-ever -- and just about ONLY bit gag to appear in mainstream US TV. (The article includes vidcaps, of course.) It was worn by Tina Louise on an episode of Bonanza back in 1968. Yes, THAT Tina Louise. She was doing a guest shot as an abducted frontier hottie, probably in preparation for her later role as a castaway on "Gilligan's Island."
The weird thing is, there were no bit gags seen on American TV until Fabiano Udenio wore one on the "Amazon" TV series in 1999. Practically another century -- certainly, another half century.
I'm not sure if there's any historical verisimilitude to the whole Indians/bit gag thing, especially since the tribe on Bonanza was clearly Hollywood Indians ... I mean, they can hear a squirrel coughing in the woods three miles away, but they don't NOTICE a bunch of burly white settlers sneaking up on them? Riiiiiight. Plus, being Hollywood Indians, they were probably mostly Jewish -- very characteristic of that tribe.
In any event, I doubt the historical use of bit gags by actual Indians on logical grounds. Either they needed to silence their captives or they didn't. And the thing is, bit gags won't silence a captive. They do almost nothing to control screaming. So I don't think they would have been used. The only reason I can think the director of whomever thought a bit gag would be right would be that it had that Western look so prized by pioneers and Indians in the old days. I mean, wood, leather straps -- it's practically a farm implement as it is.
Pity that line of thinking never caught on.