Model 12 Kleins Gun?

[Tom Doniphon]

That shotgun is in the serial number range of the WWII riot guns, not trench guns. I believe Kleins converted trench guns to long barreled sporting guns. Not sure if they converted any riot guns. They used a non-Winchester barrel and the buttstock usually still had the sling swivel on it or it was removed and the cut-out filled in.

What markings, if any, are on the barrel?