At one time, in the last quarter of the 19th century, a cosmetic treatment of barrels was done by Schilling in Germany and one rifle maker in England. Name slips my mind.
These barrels were true Damascus and then chemically etched to bring out the pattern.
Go here to see a fine example from Schilling.
http://www.worldpath.net/~jmann/Schilling%2094779%20016.jpgIt does not surprise me to see another example from a maker with the same idea or an example that was later done either by or for a gun owner.
What does surprise me is that a competent gunsmith would not know this and continues this old tale that is so in error.
Best,
John
PS--I see, missed before, that the Suhl gun that I once owned, has been posted. I can assure all that this was not faux Damascus. The barrels were made by Schilling and so marked, leaving no doubt.