The grip shape and the checkering looks like the patterns found on some of the highest grade Ithaca Flues Model doubles and SBTs.
Hopefully the serial number is high enough that a production card exists. Some strange and unusual stuff was done at North 18th Street & Windrim Avenue. Like the "Joshua Green" guns, 30-inch, 20-gauges, that card as AE-Specials --
202136 AESpecial 08.jpg
202136 AESpecial 09.jpg
Made for a number of Seattle high rollers.