If you want to do a period restoration or rebuild, do not touch it. Do not buff it certainly, and do not send it to anybody in the states to have it coloured. I have yet to see colouring done there that matches the original.
An original Metford pattern rifled barrel could be percured in an origional caliber and some searching would find the stock pattern and the details needed for a rebuild. Then you have a very nice gun worth bucks.
To do anything else is sacrilidge and a cheep Ruger#1 would be a better platform.
If you want to see how NOT to do it, do a search of .461 Gibbs on Google and you will turn up one on Gunbroker that will break your heart.

Regards