Your dates are correct if its a no-dash ....( dash 1 starts in 1986).
The S&W book says 686's were available (Square Butt, L Frame) in 2 3/4", 4", 6" and 8 3/8"....full-lug barrel, 6 shot, and all 686's are stainless.
The only reference I see of a 2 1/2" barrel is for the Lew Horton special ..and the book I have does not say if it should bear any special marks, etc if in fact it is a Lew Horton special.
S&W book says actual barrel lengths can vary as much as 1/8" ...and barrel length should be measured from front of cyclinder to the top of the muzzle. I see a lot of guns mis-marked for length because guys don't know to measure them to the face of the cyclinder. Take a tape with you when you inspect the gun to see what it measures.
I like the 686 ...(...but some of the early guns no dash and the dash 1's were recalled / and remarked by S&W as 686-M in 1987 because of a problem with the hammer nose wearing or cracking..), as I recall ....but I can't seem to lay my hands on the details of the recall. You should probably have someone check this gun ...but I also don't think 100% had the issue - or after how many rounds it started to show up. I have a 686 dash 1, I think ?? (too many guns, so I forget which dash #), its a 6", that has a lot of rounds thru it ( 10,000 or more ) ...with no issues - and it was never sent back to S&W. I bought it from a friend that didn't shoot it much / didn't like it 10 yrs or more now.../ my grandkids like shooting it...
In my area a 686 no dash ...a 2 3/4" is probably a $ 600 - $700 gun. 4" and 6" guns are selling for a little more ( $50 - $ 100 more so $650 - $750 ), especially the 4" if they're in real good shape ...and the 8 3/8" is about $ 550 - $600 and generally less desireable. But prices on guns in very good shape are up ...
