They are called "blind nuts". I can't really think of a better way to mount a wing that is one piece. If this warbird had plug in wings that might be easier to figure out. When you have an inclosed fuse there has to be a way to mount the wing that you access outside of the fuse. Maybe an internal attachment point that you acces through a hatch. I can't really think of a better way. If you find one please let us know.