It is a factory nickel K-frame born 1981 (hat tip Roy Jinks, who was in when I called). S&W logo was moved to the left side of the frame to facilitate engraving. Blued, in various barrel lengths, used by U.S. military, various state and local police, FBI, IRS-CID, Hong Kong Police, and many more. Mostly .38 special, but a small run was chambered in .357 magnum. This one sports a pinned barrel, eliminated in 1982. Gas ring changed from yoke to cylinder in this dash.
I received the revolver as a present in 2010. On the first dry fire trigger pull, the tip of one of the prongs on the mainspring claw broke off and the wheel gun became nonfunctional. I replaced it with a factory rated Wolff, also a new strain screw, and installed a slightly reduced weight rebound spring. Cleaned and polished it with nickel-safe products and lubed her up. I put on official S&W store checkered rosewood boot grips, available here. Likely good to go for another 30+ years.
A J-frame in the pocket may be more comfortable, but a K-frame is more comforting. Much easier to shoot, and has that “extra” round. Model 10-7, 2 inch. A .38 caliber M&P of the 20th century:
Shown with K5 thin Kydex pocket holster made by FIST, see here. Rides perfectly in the top pocket of several well-known brands of tactical/cargo pants and shorts. Ammo of choice is current loading of Federal Premium 125 grain NYCLAD® HP (P38MA).