Quote:
Colt was to manufacture upwards of 55,000 .455 New Service revolvers for British and Commonwealth armed forces. The majority of these were directly purchased by the British government and bear broad arrow government acceptance markings, as well as various inspection and proof marks. Not all New Service revolvers used by British forces in the war will bear official markings. British officers were expected to furnish their own kit, with a sidearm being only one of the required items. As a result, many British and Canadian officers purchased New Services commercially for use as their personal sidearms. These personally purchased sidearms may bear personal engravings, but are devoid of official markings. Most of the wartime New Service revolvers chambered for the .455 cartridge can be identified by a capital letter E stamped on the grip frame under the left grip.
I'd already pulled the grips and seen a capital "E" but had no idea what it might indicate and I'd already presumed any other markings I couldn't see had been buffed away. My working thesis at this point is it was a private purchase sidearm for a British or Canadian officer.