My friend and I were discussing the Fergusons two days ago. Years back at Kings Mountain he had been shown a Ferguson that was reputed to be from the battle. It was later apparently stolen.
I am a tad skeptical of those rifles being at Kings Mountain, but I am open to hearing about first person documentation.
I've read up on them over the years, and personally think it may be a case of Major Ferguson being the only link between Kings Mountain and the rifles.
Obviously, with one good arm, Ferguson himself did not carry a rifle, fusil, carbine, etc in his last battle.
Ferguson was the only regular British soldier in the group, which were otherwise made up of Loyalist Carolina militia from what I have read. It seems to me unlikely that a southern loyalist militiaman would have been carrying a fairly experimental and temperamental rifle (with no gunsmith support) originally only issued to Ferguson's Experimental Rifle Corps that was disbanded after September 1777 and dispersed back to their original units.
Does anyone have any further information?
Best wishes, and God Bless, Marc