In general the British do not matt or otherwise engine turn file cut ribs because thats the way we did/do it .Some makers did engin turn, matt , file cut on certain grades as decoration or to customer order . We did not as is the case with many modern Continental guns have barrels finished to shine as if they were chromed .Matting ,file cutting etc. can be used to hide the fact that the rib is not as true or well struck up as it could be as you will see on many lower end older hammer guns and cheap boxlocks.