The sloped lower leading edge aileron spar is forward of the hinge line and gets around the need for a horn on the end of the aileron, as the weight is riveted to the lower edge to balance the aileron and hence forward of the hinge line.
The hinge pin isn't crimped, the early ones had a small split pin in at the end that caused cracking, later hinge pins extend out one end, come back around and have a loop in them and is secured by one of the hinge mounting screws and nut.