It ain't Damascus and it's not welded.If it's got a barrel made with "damascus" steel or a welded seam on the barrels, then 100% do not fire it with smokeless. Corrosion may have gotten in between the layers and weakened it and there's no way to tell short of a multi-million $ lab setting or destructive testing what it's true condition is.
The strength of a modern Savage BP rifle is orders of magnitude different than an antique shotgun.
Its condition is shoot it.