Gentlemen, I have a 686, two and a half inch, square butt just like yours. It is a dash 0 gun with a sn prefix of AAC-xxxx. When I talked to Roy Jinks about it he said it was a special order for Lew Horton and is somewhat rare as only about 1500 were made. They came from the factory with the short barrel and is origional. Mine has rubber Hogues on it and it's a dream to shoot with whatever ammo you want to stuff in the charge holes. David.