Box bird gun. The executives at Field and Stream and other outdoor publications headquartered in NYC spend a lot of time at a couple of pigeon clubs convenient to town. New York Athletic Club and the Philadelphia Gun Club were two of them. The little repair that Dave shows is just a poor job of fixing a chip that exists in many double guns. No mystery there. No mystery about the date of manufacture either. Information is available on this site, early to mid 20s is the date of manufacture. Left barrel first is not only an Olin trait. Many custom pigeon guns are made to fire left barrel first, or, at least the more open barrel on the left.