The previous posters are basically correct about the gun's provenance. It is a reimported and modified British Victory, otherwise known as a .38/200 British Service Revolver. These are actually more common than the American .38Spl versions, both because more were produced, and because the US military has reportedly retained many thousands of .38Spl Victories in inventory; they were distributed to aircrew during the 1991 Gulf War!
IMHO the barrel has clearly been cut; the front sight is sitting too far back for a factory S&W 4" barrel. Actually, the OP's father should count himself lucky; these guns frequently had the barrel cut down to 2" by removing the front locking lug under the barrel, which usually degrades the gun's accuracy.
FWIW although it is marked ".38 S&W", postwar importers often lengthened the chambers in these guns to allow them to fire the more commonplace and powerful .38 Special cartridge. While this conversion isn't necessarily unsafe, it causes problems because .38S&W uses a larger-diameter case and bullet than .38Spl. Accuracy of these converted guns is usually below par due to the undersize bullets, and the oversize chambers can cause .38Spl cases to bulge or split, creating ejection problems (and ruining the cases if you intend to reload them). Some shooters with converted British Victories stick to the original .38S&W cartridge for reliability and accuracy reasons; there is no reason the original cartridge cannot be fired if the chambers were lengthened.
BTW the reason for the generous space between the serial number and the "V" prefix is that the gun originally had a swiveling lanyard loop in the butt. The hole has been plugged and plated over. (On many nickeled Victories, you can see the outline of the plug through deteriorating nickel finish.)
Two warnings:
- Keep +P ammo far, far away from this gun! Early .38M&P cylinders were not heat-treated as well as later examples and may come apart with sustained use of +P.
- Early WWII-production S&Ws incorporated a "wing" or "pivoting" hammer block that is hinged to the sideplate and is pushed out of the way as the trigger is pulled. This safety device, although it's better than nothing, is prone to failure because rust, grease, and/or dirt can jam it in the disengaged position, and it is known to break with extended use. Unless it is inspected for proper function, do NOT count on it to prevent accidental discharge if the gun is dropped with a loaded round under the hammer! If the gun will be carried, it is wise to carry it "five-up" with an empty chamber under the hammer. (In 1944, this hammer block was replaced by a superior sliding design, which is nearly immune to breakage or jamming, and is more fail-safe, particularly if the revolver is dropped with the hammer cocked. The sliding design continues to be used today.)