Many of these were imported by the Confederacy, but I believe your serial number predates our War Between the States. Mine has a Confederate inspector's cartouche stamped into the wood below the trigger guard.

I did a search in the Confederacy for W.Watson and found 393, so the likelyhood that it could be attributed to a specific soldier is slight.

Do send me some pics (especially of the damaged grip) and I'll see if I can help.