I have a very early 1911 that I am trying to ID the inspectors mark which is a K on the rear trigger guard. It has a VP proof mark in a triangle at the left front of the trigger guard. I've search all the internet sights related to 1911 pistols and can't find the inspector mark this pistol has. The pistol has a three digit (C5XX) serial number. Any information on this inspectors mark would be appreciated.