This Colt 1908 Vest Pocket was shipped to the Shapleigh Hardware Company in St. Louis, Missouri on December, 28th, 1916 in a 50 gun shipment.
This Colt 1908 Vest pocket is unique as it is inscribed on the right side of the frame with the text "METROPOLITAN POLICE". The other custom/unique feature about this pistol is the magazine. It has a custom base plate with a finger extension to help provide a bit more stability while firing.
It's unclear when or where the inscription work and custom magazine was done on this pistol. From the data from the factory letter it was not done from the factory.