Fox Collectors

Recently found a Sterlingworth Wildfowl for sale Were these guns built on a Becker type Super frame? Where do they fit in Fox/Savage production timeline?

Thank you sir for your input , there are probably more undiscovered variants in existence . This one was just too intriguing to pass up . That's a fine looking X grade by the way !

The setter is also pointing in the opposite direction than a 1912 gun i have .

Would a set screw to the screw under the top lever be characteristic to X grade finish work ?

Is there a possibility Gough engraved this gun ?