it is a long story in the history of Colt firearms.
This is the quick story as i remember it.
The Texas Navy bought a hundred, as I recall, of the Paterson revolvers which kept Colt in business for a while. The Navy did not like them and the Texas Rangers got some and used them to great effect on Comanche Indians. Look up the Battle of enchanted Rock.
During the Mexican war Sam Walker, who remembered the Paterson revolver, got with Colt who designed the 1847 "Walker"" revolver sold 1000 of them to the Army, got back in business and never looked back.
That roll engraved scene commemorates that navel battle and what the Texas Navy did for Colt.
It became kind of trade mark and identified copies of the Colt guns. It was first used on the 1851 Navy revolver.
Bunk