Strip the entire thing of the clear coat, wipe the wood down with kerosine and then let it dry for a few days, and then do several coats of linseed oil applied with a rag, coat it a day apart for several coats.
The metal will likely be needing a blueing job if it was really sanded down (which is nearly a criminal offense against a gun, but... it is what it is). You can have it blued by any reasonably competent gunsmith. If the metal is in good shape without deep scratches caused by sanding, you might actually just be best leaving it alone. If it was just steel-wool polished it's likely just best left as-is.
The receiver might have been case hardened, can you see any remaining color there? Redoing that is a job for a real pro.
Willie
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