I own a 4" I bought new April 5, 1985 at a police equipment shop. It is called the Distinguished Combat Magnum Revolver Model No. 686. There was one for sale on Guns America a while back for $595, same sku as mine 104202.
M-686 4" .357 Distinguished Combat Magnum Older Model Smith & Wesson Revolvers > Full Frame Revolver for sale, gun classifieds or gun auction from CJS10. Buy or bid on this M-686 4" .357 Distinguished Combat Magnum Older Model in the category Smith & A picture of it can be found here, along with a partial view of the original S&W paperwork and box. I retained all of mine as well.