I have acquired a Guildhall Pipe. I know it is part of the Comoy family. It says Made in London in a circle with England below it. It has 483 on it. AND it uses the 3 silver art decco lines instead of the C for Comoy on the stem. Any idea when they switched from the three lines to the C? It also has a 3 hole stinger in it. I can't find much on dating these 2nd Comoys but I figured that stem change might be the biggest help. Any ideas?