Must be a common problem this weekend. My drawing 17 only shows 12 rivet locations on the bottom of the wing, but there are actually 21 holes. I just assumed - it appears correctly - that the holes not shown on the drawing are for platenuts. However, if it hadn't been for the recent service bulletin on wing installation, along with the drawing which showed a platenut on the bottom, I might have made a much different assumption. As it was I marked the holes in the bottom fuselage skin with a hole duplicator, drilled with a number 40 bit and hit every hole. Then enlarged for the 8R8 screw.