Flingarrows,
If you bought an Ultra Slug 20ga, the steel bar is in your stock from the factory. If you want to check, grab a Phillips screwdriver and remove the recoil pad, it will have a Phillips screw holding it in place.
Get out there and shoot that gun, mine likes everything I have shot out of it. I really like the Remington Ultra Core-Lokt and the Winchester Partition Gold slugs. You wont believe how mild the recoil is and these guns are shooters.