You might consider casing it up and flying out to Las Vegas next month to the Antique Arms Show. Many qualified gunsmiths and a bunch of this membership will be there to give assessments of your gun. You'll learn a lot about doubles and see thousands of them all in one place.

I'd like to add a word of caution: don't attempt any restoration at all before you learn about this gun and how proper restoration is done. Wire brushes and sandpaper have ruined many potentially restoreable guns. Dont do it.