Raimey, I did not see any. I had to use a loupe to see most of what I found but I don't see a Nitro. There is a crown over W I didn't mention and what looks like 2 diamonds on one tube. There is no name or marks at all on the outside of the tubes(upper side). No gauge or makers name on the rib. Usually there is something there. It almost looks like a set of replacement barrels. There is very little on the water table except the Nimrod Hunter on the breech and the serial#. One other mark I can't make out( maybe an eagle) and a crown over U.
