Well, I'm guessing this isn't Sauron's sword. I have a theory. This seems to be a prototype Witchking sword. There are pictures on the Fellowship EDVD of Sauron (or a Sauron like character) holding it. Could this be the Witchking when his armor was quoted as "looking too much like Saurons?" That would seem to make sense, that this was going to be the Witchking's sword before they changed that sword to his current one, and then afterwards they changed his armor. Perhaps they might give this sword to the Mouth of Sauron. The Weapons and Warfare books says that he and Aragorn fight briefly before Sauron's army emerges from the Black Gate.