I've talked with Billy this morning, and he says the following:
The barrel on this rifle is 47.25 inches long, and it's .32cal. Close examination doesn't show the circular design that Ken asks about. The caplock is not original, and he's basing this on the fact that the moitise was not made for the lock presently on the piece. It's significantly different. The nose cap is missing, and he thinks the original was brass but that's just a gut feeling. The trigger guard is not original in his opinion, and again because the moitise is different. The thimbles are brass and he thinks the one closest to the muzzle is not original, but is a replacement because it is attached by flairing while the other two are pinned. The rifle was found with an old family in Union County (Blairsville,Ga) and the previous owner says that all he knew was that it came from somewhere in Tennessee originally.
Billy has almost finished a close copy he's making using a 44" .32cal Rice barrel and a Silar lock from Jim & Barbie. The stock is flat sawn Cherry off Billy's GGrandad's old homeplace in Union County. (Billy is directly decended from John Gillespie, the Union County riflemaker along with his brother James Gillespie). Our plan at this point is for me to swing by Union County and pick up the original and Billy's copy and bring both up to Mel's Show at Lake Cumberland next month.