Nope thats looks like its for the round barrels. http://www.gunbroker.com/Auction/Vie...Item=220701808

This auction is closed, but if you scroll to the bottom there is a picture of the mount that you need. Just needs to be a 9953. I know that there are some other scope mounts that work on the GM barrel. But I could never find them. Maybe if you called GM again and talked to someone in the shop.