vpnavy:
You have a Victory Model, probably manufactured in 1942 or early 1943.
The patent dates are for the .38 Military & Police Model of 1905 4th Change introduced in 1915, the Victory Model was a milspec version of this gun with a phosphate finish & smooth grips.
G.H.D was the government inspector at S&W during WWII, Guy H Drewry IIRC.
Barrel length is measured from the forcing cone (front of the cylinder). Yours is a 4 inch model.
The US Property marks are due to Smith & Wesson production being taken over by the Government during WWII. All distribution went through a government agency.
The S stamp with the serial number means your gun was sent back to S&W and had a hammer block safety fitted. In 1944 there was a fatality on a US warship when a dropped gun fired. S&W redesigned the internal hammer block so it would not fail if the gun was dirty/gummed up. These guns had a VS prefix. S&W also retrofitted some older guns. Yours is one of them. These had an S stamp added to the serial number or on the side of the frame.
The VS is spaced apart from the numerals because S&Ws stamping machine only went to 999999. In 1941 it clicked over to 1, so they added a hand stamped V for victory as a prefix to differentiate it from the earlier guns.
The S & 67674 under the cylinder yoke are assembly numbers, used to track parts in the factory. They have no meaning after the gun was completed.
Don't post a full serial number online, use xxxx as you have. This prevents someone with ill intent from reporting 'their' gun stolen by you and giving the police the serial number to search your house for.
As your gun appears to be in excellent condition and has the safety modification it may have some value to a collector. If you ever decide to sell it I recommend you advertise here or at the
www.smith&wessonforum.com You will probably get a better price from a collector with a spot to fill in their safe.
As for use at the United Nations, unless you have some documentary evidence, such as a letter from the original owner, it cannot be proven and adds no monetary value, but does make for an interesting story.