There's some really interesting discussion of the Indian question in Peter Alexander's The Gunsmith of Grenville County (eg p 13-14), who quotes other articles. He quotes a letter from trader Daniel Pepper to Governor Lyttelton of 30 November 1756:
'I think it highly necessary to inform your Excellency that the Indians are daily getting into the Method of useing Riffle Guns instead of Traders which they purchase wherever they can at monstrous (sic) Price, as they can kill point Blank at two hundred Yards Distance.'
He also quotes an article claiming that the North Carolina Catawba leader, King Hagler, was reported by eyewitness Maurice Moore as being buried in 1763 with 'his silver mounted rifle, a fine powder flask, gold and silver moneys, tobacco and ... other personal possessions.'
There's lots more of interest I'll try and sift through here. But one really fascinating point occurs to me: if rifles were being buried as prestige belongings, is that what happened to most high-quality longrifles that were made specifically for Indians? There don't seem to be many longrifles surviving with Indian style decoration, so maybe that's what happened to them. Unfortunately we'll never know from archaeology as Indian burials are sacrosanct.
There's a great PhD topic, or book, in this - there must be plenty of archival material like the letter quoted above which have never been studied, at least never from this perspective.