I began drilling the F-757 gusset for the right side of the fuselage. I got the 4 prepunched holes and the five through the longeron, including the three that have to be laid out. Then I noticed that I did not have the F-721B canopy aft deck securely clecoed to the longeron, which allowed the longeron to bow out about 1/16 inch. The only damage done is to the F-757 gusset which should be relatively inexpensive to replace.