It looks like a Mag-Na-Port custom to be. They're located in SE Michigan and are known for their EDM barrel porting. The company was started by Larry Kelly and his son Ken now runs the business. In addition to porting, they offered custom aftermarket packages.
Mag-na-port International--Home Page
The barrel was certainly ported by them. The polished stripes on the cylinder are typical of their custom work, as are the engine-turned/jeweled trigger and hammer. This indicates they did an action job and they usually numbered the cylinder chambers. The barrel flats gave them a lot of area to do more engine-turning.
A photo of the other side of the gun would be helpful, but I'm pretty sure that started out as a S&W Performance Center Hunter. There's NO WAY I'd sell that for $650, it's worth much more.
Here's a 686 Mag-Na-Port custom that Collectors Firearms sold some time ago.