Joe: if the barrels have a crolle pattern, they ARE damascus. You can bring out the pattern somewhat by rubbing a soft cloth with a dab of white vinegar, under the FE where it will not show, then oil the spot.
No. 0 guns were offered with "London Steel" after about 1907 and were so marked on the bottom of the barrels just forward of the flats.

"Mirror" bores in a 115 y/o gun are very suggestive of previous honing, and the gun should not be used, with ANY load, until careful measurements are made of the wall thickness; from breech to muzzle.

Regarding safety please see "Is my shotgun safe to shoot" in the General Information FAQ
https://lcsca.clubexpress.com/content.aspx?page_id=274&club_id=43784