Star Wars Death Star Playset Laser Cannon Gun Chair Floor Piece Vtg 1978 - Parts

Cannon is missing the end piece below the main forward laser. Main laser looks like it has been glued. (see photos) I'm not sure how the cannon fits onto the floor piece or if there are parts missing. The underside of the floor has some glue marks, and a piece of a broken support beam is stuck in one of the holes.