As with most aftermarket barrels, all of the identifying information is stamped on the breech end. When the barrel is cutoff, the info goes with it. I make it a practice to mark the barrel, under the forearm, at the same time that I mark the caliber, neck dia. etc. on the side of the barrel.
I found a serial number under the barrel. Are you saying that this would not be the original mark? And that the original mark would have been removed in the chambering process?
Lilja, Hart, Stainless Shilen, Lothar Walther that Brownells sells, Krieger, and Parker Hale Midland are premium barrels that have been lapped at the factory.
I can tell they were lapped with a 20" Nite Ize Fiber Optic Adapter/AA Mini Mag-Lite® Combo flashlight accessory and a magnifying glass.
All Custom barrels are marked on the breach end and or the muzzle end because of contour
or tapering and removed when the barrel is chambered and crowned.
The only marks that are on the outside of a custom built rifle are the proof marks or the smith's
identification/serial number for his benefit.
As stated there are a lot of hand lapped Custom barrels but trying to prove which is which
is very diffacult if not impossible unless you know the smith that built the rifle.