The overall proportions of the gun look like a K frame to me, but there is no need to guess.
A measurement of the cylinder diameter would let us be sure which.
Whether the cylinder is recessed for cartridge rims or not would tell us whether it was a Magnum or a rechambered Special, unless it were an L frame, which I doubt. A measurement of cylinder length would help, too.
I see a number of oddities.
S&W made some full lug M14s and a very few full lug M15s, but they are Specials, not Magnum.
The extractor rod appears to line up with the front latch, indicating the barrel was made for that frame size.
The top strap is not only checkered, it appears level, without the slight step down to the barrel rib common to all my adjustable sight S&Ws except the 2.5" M19.
The rear sight is not standard S&W, the elevation screw is the wrong type and wrong location.
The hammer spur does not look quite right as to width and angle.
The thumb latch may be the old type, but the picture is not clear enough to be sure.
There is no right side picture to show sideplate screws, although I think I detect a cylinder stop screw at the front of the trigger guard in the tiny bottom shot and the left side view.
Considering the location, I am wondering if some enterprising gunsmith started with a WWII Empire surplus .38 and made everything "modern" from scratch in reasonable approximation of S&W features and markings.