Definitely worth a letter. Prewar ODs with King modifications are a class of collectible in their own right.
The humpback hammer did not become available until 1938, so if this gun shipped as early as the frame number allows, it would have left the factory with a standard long-action hammer. If you feel like pulling the sideplate, I would be curious to know whether King marked the inner surface.
This is the only King-marked sideplate that I have come across. I don't know if 1941 is a year or a job sequence number.
That sideplate is mounted on this gun, 46207, a McGivern OD that letters with the five inch barrel.
This revolver's action has been modified to shorten the hammer throw: the hammer stud has been relocated slightly. This mod was initiated in the 1930s by J.D. Buchanan, a Los Angeles gunsmith. King eventually offered a similar short hammer throw option that involved no modification to the lockwork but was achieved with a drop-in redesigned hammer.
This gun was previously discussed in this thread, in case anyone wants to compare similarities and dissimilarities to the gun in the original post.
A King-Marked McGivern Outdoorsman with Shortened Hammer Throw
I think it is possible and perhaps even likely that the OP's gun left the factory as a McGivern Outdooorsman and that King later modified it at customer request. Fine specimen.
Glocknroll, would you be willing to PM me the full serial number for my data base? I track McGivern ODs, and I'd like to follow this one's number as a candidate for membership in the list once its status is confirmed. At the moment I know three dozen specimens, some not seen but known to have existed from records. The next lower serial number known on a McGivern OD is 46687, and the next higher number 54742. There are four confirmed McGivern ODs in the 46xxx group. If validated, yours would be number five in that range.