After I clecoed the aft spar to the ribs for test fit, I realized that the middle two holes that mount the 3rd and 4th rib to the aft spar are not lined up with the pre-punched holes in the ribs.
I posted the question with a couple of pictures on =VAF= and got a response from the factory that I need to drill new holes in the rib using the spar as a guide.