Bruce is right. If you see page 7-12, step #2 it calls for you to put a slight bend in the leading edge of the left skin.
 
I had a few gaps in my rudder LE. I drilled out the rivets and did some re-forming to remove the springback which causes the gaps. In a few places I added a rivet between the existing ones and also put an aluminum washer on the inside of the rivets (similar to those used on the baffles) to cinch things up better