I'd say definitely a redial and the hands are not original. The case is a correct "Cosmic" case and looks all original. These cases can be problematic because oftentimes people wear them for a long time and that causes the gold plating and base metal to wear away on the underside--mostly at the angles. If it was steel, then it probably could be stripped and soldered, but it is actually plated brass. It isn't at all worth the effort...much easier to find one in nice shape. If its cheap enough, then you could possibly find a replacement case online--I find that they come up alot as people seemed to enjoy harvesting the movements out of these.
What makes you say Cal. 751? These were never chronometer rated and the reference number further supports that (ie 166 vs 168). This should have a 752. If it has a 751, then: 1) the original movement has been replaced or 2)the train wheel bridge has been switched out. The most likely explanation is that whoever advertised this doesn't actually know and made a guess or is trying to mislead people. There are a bunch of sellers on ebay in particular that seem to like listing the chronometer movements....possibly in an effort to get a premium from an unknowning buyer.