M1897 Trench question

[Shooter88]

Hello all. First post here. Anyway, I have a Winchester 97 built in 1918 that appears to be a legitimate Trench gun. After reading Canfield's book, I believe it to be a WW2 rebuild as it exhibits the following characteristics:

-parkerized
-WW2 style stock
-metal checkered buttplate
-four row ventilated heat shield ("W" stamp on left side)

Other traits it has

-serial number is in correct range of a WW1 trench
-barrel is exactly 20" measured from the bolt face, and is marked "CYL"
-hand stamped flaming bomb and "US" on right side of receiver just forward of the ejection port
-has the "WP" proof stamped on top of receiver and barrel
-heat shield fits snug on barrel without shims or sleeve.
-barrel has three grooves in the bottom.

One thing I am not sure of is that there is a hole about a 1/4" from the end of the muzzle that has been filled in with a black substance. The hole itself is not threaded. Right now I'm thinking Bubba, but wanted to check with you guys first. Thank you.

[p246]

One of the experts will be along but I think Bubba did get ahold of it sometime in the past.

[Shooter88]

One of the experts will be along but I think Bubba did get ahold of it sometime in the past.

Thank you. Here are some pics of the whlole gun. It also has a peculiar flaming bomb stamp above the ejection port which I think is also Bubbas doing.

[Shooter88]

More pictures

[Tom Doniphon]

The WW1 trench barrels were not drilled for a sight bead. So someone has definitely messed with the barrel.

If it were arsenal rebuilt by the Military I would expect to find an arsenal mark on the stock or receiver and a P proof mark too.

[hyrax222]

Stamping ahead of ejection port, right side looks correct. Butt stock of a later type.