I saw this yesterday, and honestly, I kind of hope he does. It's an attack on his brand and on his reputation. If they're going to spread lies and bullshit then they should be forced to pay for the consequences as frequently as possible.
But knowing Joe, he's a pretty "who cares? screw them" type guy, so he probably won't. It would be interesting to see him do it, though. Even though we know they'd settle pretty quickly.