There is a difference in the "style" and execution of the oak leak motif found on different grades of Scott guns. Most Excellentias, even some Premiers display a oak leaf motif that is carved in the metal by graver. The type of execution shown on the very highest grades (like the g&h gun) is done with a hammer and chisel. A pretty unique technique that Mr. Brown was known for, and a technique that very few engravers in England could replicate.
Please correct me if I'm wrong.

Dustin