I'm not one to say "If it were my truck" but... ... The correct way would be to drop the headliner and Tig or Mig weld a new piece in just enough to fit into the existing hole,then re-drill the hole,and use urethane around the hole(the same stuff they use around the windshield to prevent leaking)If Mig welding,make sure to protect your interior from slag and cover windshield,the sparks from weld will leave pits on the glass. If you dont own or have access to the above,you can always do the nut and bolt method,even though thats pretty barberic.