A Barnett. Trade gun. Similar others by other builders/companies . The serpentine lock plate will be similar.
Economy too. Flat or folded flat butt plates. Ect.
Schools of build varied of course. As did resources.
English fowlers evolved as others but seem more ornate even during the golden age.
Their market and smiths ability to source materials to build with at greater leisure perhaps apply.
( I believe Chambers built this in America not all that long ago to represent a mid 1700's style.)