Graham Greener refers to- The Trap Gun- as inexpensive,10- guinea.His book also shows a 9-guinea gun (no engraving).I have a Trap Gun from 1887,they look identical,and it does not appear that the workmanship was skimped on.
I found mine in it's original case with the owners name,John G.W. Dunn ,(the son of a wealthy Philly Banker)engraved on the name plate.