It was not uncommon when it became common knowledge that pattern welded barrels were "time bombs" wink to return the gun to Hunter Arms for steel barrels, and the factory would stamp the original SN on the new barrels.
http://www.lcsmith.org/faq/replacement.html

Only way to know is with a Research Letter
http://www.lcsmith.org/shotguns/researchdivision.html

but there may be limited information depending on when the new barrels were fitted
http://www.lcsmith.org/faq/researchltr.html

Crown steel was used for the Pigeon Gun on introduction in 1893; Nitro steel after about 1898. Steel barrel replacement cost was about 1/2 of the cost of the gun (by grade), and some sportsmen elected to use the less expensive 00/Field grade Armor steel.

https://sites.google.com/a/damascusknowledge.com/www/home