One of my partners at work brought in a Merrill carbine he'd inherited. It had a "CS" carved in the stock, he thought it might have been captured.
I noticed a name inscribed on the patch box - a little digging shows the owner had been in the 3rd Tenn. Cavalry, his wife died in 1864, he was captured in late 1864, was held in either Cahaba or Andersonville, was on the Sultana, died from scalding on May 9 (12 days after the explosion). There was a pension issued under his name, so he must have had at least one child. Those were tough times.
That's a great find, Steve. I'm sure we'd all like the details about finding it after you make sure that well is dry.