Recoil Rob, the two serial numbers mean that the Lefever factory installed a second set of barrels. This is a common marking for Lefevers that had a second set of barrels installed at a date later than the original manufacture. The different engraving patterns on the lugs are not a mystery. A different engraver engraved the second set, or, maybe the installer of the second set of barrels never saw the first set. My opinion, factory two barrel set. Nothing wrong with the price paid on gunbroker. I would have bought the gun when it was originally sold at a Pennsylvania auction, but I was interested in other items.