I have no doubts in my mind that it is a factory nickel gun. In that time frame it may or may not have come with a wood box. I would say more than likely but not 100% certain.

I have cleaned nickel guns that were far worse than that one and they came out practically new looking. That one appears to have basically dry finger prints on it. I dont believe there is a need for a polish any more aggressive than a Never Dull cloth.