Mattox Mike,
a re-stock could have been done in the first half of the 19th century.
I have a John Twigg that has been re-stocked a Very long time ago. It's a good job, but not a Twigg job.
This is one that maybe Joe P. could help with.
I am wondering if this is a Ketland made barrel or even gun, and the silver escutcheon was stamped with a retailer's name?
My barrel with the same (as far as I can tell, mine is in worse shape) makers mark between proofs, also has a silver escutcheon, but mine stamped "Oaks, Horesham"
The wood for-end cap has me a bit bothered, as it seems butted up and glued.
Horn caps fitted over a tapered and stepped for-end extension.