Winchester Trench Gun Barrel|Winchester Shotguns|Forum|Winchester Collector

First time posting.

 Was told to  try here, for more info from Trap55 / Bert H. on GB.  Not For Sale

Picked this up at a Gun Show.
Looks to be for a Winchester Trench Gun. Model 1897 fixed  receiver  Barrel only

It’s a 12 Ga 20″ with the correct 3 three inletted area for screws for the Trench gun Shroud
Appears to be un used, with grease still inside the bore, no markings on barrel from use
Has a 41- and index mark on the bottom of barrel and No proof marks on barrel.  Finish is 98% Blue.

But …. seems to be strange. the Barrel is Marked Made iIN THE U.S.A and the 2 /3/4 CHAM CYL” is in different script.
Not Roll Marked for Model 12 or 1897 Last Patent date is July 5 10

Too good to be a  repo

What might I have here?