Gunsmith question on Shotgun Barrel salvage

[Copross]

I got a 20 inch Remington 870 12 ga barrel the other day - surplus LE training barrel. An approx. 1/8" threaded hole with a screw is in the side of the barrel approx. 2 1/2" from the breech/chamber - I assume to negate a live shell being chambered for safety/training reason. My question is with the screw removed, can the hole be welded and the barrel be safely used again? Thanks for any input. Doc.