If you read the ad carefully it refers to the barrel being hand forged by Hershel. It does not say any of the other parts were made by him or that the gun was stocked by him. Again, I believe the barrel was a project or demonstration done in association with a show a couple of years ago and the gun was actually stocked up by Dan Casey in the Woodbury style.
If it were an all Hershel-built gun with a hand forged barrel the asking price would be a steal.
Guy