There's a longer article on CNET about this that says that the new system will be backwards compatible with existing NXT robots.

If it is a two wire socket, the screw probably won't be grounded either since the box itself probably doesn't have a ground wire coming to it. At least that's the case in my old house. I had two wire sockets virtually everywhere and worse the outlets were old enough that they weren't holding a plug properly. Short of tearing open the walls and running new wires, the only option was to replace them with GFI plugs.