Nice gun, great price. I have an early 90's vintage 686, very lightly used. Just FYI, last summer or so I took the side plate of my 686(& a few other S&Ws). It was clean inside but rather dry. Depending on how mechanically inclined you are you may consider removing the side plate for inspection & a light lube job. When I get a somewhat older gun with an unknown history I like to give it a good once over. I surely wouldn't want to talk you into something your not comfortable with & mess things up, just an idea.
There are instructions for side plate removal on the web in various places, U-tube & others.