I carefully drilled out the rivets holding the mistaken hinge brackets for the right aileron and clecoed them back in the correct way. I've already ordered replacements for those two brackets, since the countersinks on the wrong sides are not recoverable, so it'll probably be at least a week before I receive the new ones from Vans. However, I was still able to use the bad ones to check the correct faces of the right aileron skins and make some progress on them. I started by removing their blue protective plastic, dimpling them to eventually receive their flush rivets, scuffing the areas that will receive primer, and masking off the trailing edges (that will be receiving adhesive for the trailing edge extrusion). Then I sprayed them with primer where they'll contact the ribs/stiffeners.
(This was a short session because I spent the rest of my evening doing some unrelated metalwork for the ceiling fan in my hangar, which needed the 5-foot downrod support tube to be cut down to 3-foot, and re-drilling the holes in that tube.)
What's next? I'll need to practice some back-riveting, and then move onto attaching these stiffeners to the skins.