I would think not. If you don't have to buy a ticket or a dining plan for them, you wouldn't get a mug. Just like you can't get FPs for them, they don't have/need a ticket.
He is on the reservation becuase all heads are counted towards room occupancy, no matter how tiny the head.
In regards to recieving.a mug, no. You did not buy a dining plan for him, so he would not receive an entitlement that was not paid for. You are confusing room occupancy counts with the dining plan.