I don't know if the photo show enough, this is a 19-5:
Model 19: The .357 Combat Magnum Caliber: .357 Magnum/.38 Special. Double-action revolver built on the square butt K Target frame with four screws. Blue or nickel finish, originally available in 4” ribbed barrel only, with a 1/8” Baughman Quick Draw on a plain ramp base front sight with micrometer click adjustable rear sight...Later versions with red ramp front sight and white outline rear sight.
Supica, Jim; Nahas, Richard (2006-12-20). Standard Catalog of Smith & Wesson 3rd (Standard Catalog of Smith and Wesson) (p. 172). F+W Media, Inc.. Kindle Edition.