I'm betting it's a K38.
This is a target-sighted version of the 1905 Hand Ejector Military & Police. There were a series of target revolvers introduced before WW-II, as K-22, K-32, and K-38. Some of these were very rare in the pre-war series.
These revolvers are most famous in the postwar series, starting in 1949, having click-adjustable rear sights and heavy six-inch, wide-ribbed barrels, with the various caliber models matched in weight. In 1957, these were given model numbers 17, 16, and 14 respectively. The model 15 Combat Masterpiece was the K-38 with four inch, narrow-ribbed barrel.
Your K41058 falls in the 1948 serial number range, and so probably has the narrow-ribbed barrel.
The large target style stocks became available in 1951, so these were probably fitted later, to replace large-diamond magna style stocks.
Above inf mainly from Standard Catalog of Smith & Wesson , Second Edition.
The K-38 was a first class target arm for bullseye competition. It was easier to hold for long strings of slow fire than the larger, N-frame target revolvers, though some considered it was TOO light in weight to "hold steady."
Some postwar police agencies were nervous about allowing their officers to carry magnum revolvers and restricted them to .38 Special arms. The six-inch barrel of the K-38 provided all the practical velocity available for uniformed personnel, such as California Highway Patrol. Many of the old-timers of Los Angeles PD clung to their longer barrel pieces even after the newer officers were required to carry the four-inch models.
Best,
Johnny
