A head rail or head rail assembly for an architectural closure, the head rail including an elongate front wall having left hand and right hand longitudinal ends and an elongate bottom wall having left hand and right hand longitudinal ends. A left hand end structure is positioned adjacent to the left hand longitudinal end of the bottom wall and a right hand end structure is positioned adjacent to the right hand longitudinal end of the bottom wall. A first slot is defined between the left hand end structure and the left hand longitudinal end of the bottom wall and a second slot is defined between the right hand end structure and the right hand longitudinal end of the bottom wall. At least one of the first and second slots is closed by a removable closure.