I picked up a 686-4 tonight and curious as to how old it might be. Under the yoke it has CAU9*** 686-4 It has a 6" barrel.
On the right side of the gun I see 2 screws, but I'm thinking a 3rd screw is being covered by the Hogue Wood grips that are on it. The only S&W trade mark logo is on the left side under the cylinder release...nothing on the right as far as a logo. Does have the Made In USA info.

Would appreciate any info. Sorry I can't post a pic at this time.