So I had seen in the past another elsie that had a vent rib added at the factory. It belonged to a friend, and the first time I saw it I was convinced it couldn't have been done at the factory. But I learned that some were later fitted at the factory and the engraving on the end of the rib didn't always match the rest of the gun. But that gun had everything with it, original shipping box, tags, etc. and all receipts from the factory.