This photo shows an aileron stop installed on the forward side of the support between the spar and the support. In order for the installing mechanic to reach the required aileron travel, he had to grind the stops almost completely away. He relied on an exploded view from the parts or maintenance manual which are WRONG, Those are not “approved documents. Only the factory drawings are approved and they show the aileron stop to be aft of the support. The drawings are not public information so they are not published. Service Kit 121A shows the correct installation with the stop against the support on the aft side. When installed as described, the aileron travel is correct, usually without any filing of the stop.