There are some very knowledgeable experts posting on this one.
I would second Ross that the Bernard tubes top the other pattern. Bernard pattern was always an A list item.
Also as Daryl stated. There is no evidence of anything but German influence. The German gunmakers had a long tradition of damascus barrel making.
We are just not used to hearing about it.
It really is a mistake to think that only one center produced parts for resale.
Parts were coming out of many centers through out Europe including Belgium, England, Germany, Spain, Italy and France.
The trade was much larger than we are used to thinking.
Ross, anytime you get tired of carrying that big old 10ga around, you let me know.

I know some grouse that it should be introduced to. It really is a great example!
Pete