I'd be all over that like a duck on a junebug. Those are great shotguns and if and when you want to sell it it's worth more than $600 to a lot of folks.
Be advised that to make the 121 series go bang you have to drop the first round into the ejection port unless it has an aftermarket 'Benelli button'. If it has the Benelli button it only takes a fleck of the wrist to release a round from the magazine.