I don't have the 1901 literature you refer to rating Royal, twist, Damascus, steels, but guess the literature might list the prices of each type, and might not be a "rating". At the time, fluid steel barrels were becoming cheaper to produce than the composite steel barrels. A few years later, the composite steel barrels were becoming more expensive to produce and after WW1, very few were seen on new guns.

http://www.bakercollectors.com/