You're quite welcome. I got the date from Nigel Brown's book "British Gunmakers". It has a good deal of useful information. There are two volumes, the first concentrates on London makers, and the second is dedicated to Birmingham, Scottish, and other regional makers.
Nice gun! I recently bought a Stephen Grant hammerless sidelock myself. Grant made some very fine guns.
IC is murder on clay birds even when that bird really gets out there you can get a nice starburst break if you point the gun right. I only shoot 7/8 ounce loads in a side by side for 12 and 20 gauge, and it smashes them if I do my part.