http://www.remington.com/product-fam...-shotguns.aspx
If in doubt, bring to a gunsmith before firing. You can possibly remove the forearm and clean a bit of the normally hidden surface and examine; I also understend that there is a test involving treating a small surface area with acid to reveal the steel patterns can be done; but that is beyond me.
To safely shoot the gun you can have a set of sub caliber tubes made to fit the gun if you want to shoot it that badly.