I recently bought an Ithaca "Knick" SBT and I can't figure out the date code from the serial number from either Walt's book or the Ithaca website. It's a grade four with early style engraving, and the serial number is 2900XX-T. That would fit for a 1918 Flues gun, but I believe my gun is a Knick. Any help would be appreciated...Geo