Your 686 should have come from the factory with a set of target grips on it as shown in the thumbnail photo in post 2.
As you know, the AHD 11XX is the serial number. The rest of the numbers on the gun were assembly numbers for the factory. They mean nothing to the gun's owner.
I have been told that the factory used to stamp symbols into the frame of the gun under the grips to indicate work had been done to the gun, such as a re-blue, etc. They seem to have abandoned that practice long ago.
The book says S/N AHC 1687 shipped from the factory in January 1986, so I'd guess the date of your gun is early 1986.
Your no-dash seems to be one of the last ones as the 686-1 was introduced sometime in 1986.