200: Rattle ceoming from underside of dash

My 200 has developed a rattle that seems to be coming from somewhere near the pedals/ under the dash.

Anyone experienced similar? Its most prevalent at town speeds so around 20-30mph. Below this I don't hear it. Seems to be something is just vibrating but I can't pinpoint it.

Also, my passenger side has a little black bung in the door frame, but the drivers side doesn't. Should it?