I have a Fox Sterlingworth Model 1911 Pin gun whose fit and finish is definitely better than the later Sterlingworth's and in my opinion is worth a little more compared to a similar condition later gun.
Serial number 57979 shipped October 24 1911. I think it would be considered their Brush model as it has 26 inch barrels choked IC and Mod and letters accordingly. A very nice handling gun that locks up like a bank vault.

Jolly