Very nice kit no matter what the present finish!

That said, I would opine that the action was polished, engraving recut, then nickeled.
One can see slight dishing near one screw hole, faint scribed lines to align the Thomas Bland and Sons, as well as faint fore/aft streaks from polishing. The rear sight, if original unpolished finish, shows vestiges of old very thin pitting as well.
Of course I could be wrong, been before.
I suppose one "could" get the nickel stripped and the whole recase colored for some ungodly cost and if there were a reliable outfit to do proper case colors as St. Leger in the UK used to do.
- Mike