Looks to have a very desirable 3" barrel, but from a later time....take the stocks off, is this a square butt?
Open the crane, do you see a marking CS-1? or CS-3?
Manufactured approximately November, 1984. If that is a 3" unmodified barrel and also a CS Model, the sky is the limit in the condition it is in with those stocks. Probably $1500-$2000, depending on how bad someone wanted it. If it were mine these days with the outrageous pricing on vintage Smiths, I would take no less than $1500 for it. Good luck.
from the face of the cylinder to the tip of the barrel
I believe that revolver is re-barreled because the ".357 Magnum" is on the left side and "Smith & Wesson" is on the right side and for that era of 686, it should be the opposite.