In addition to the shape and pin locations, the Inscription regrading two inch cases seems to appear on guns made by S&W and those that were rebadged. My 2" 12 ga. by Charles Hellis is one such gun. Also the guns made by S&W often have the initials "JA" on a barrel just ahead of the flats. Joseph Asbury was a top barrel and action maker in the Birmingham trade who made most of the actions and barrels for S&W 2" 12 ga. between the wars according to this resource:
https://www.shotguns.se/html/uk_trademarks.html
Gil