Deburred the attach angle holes. Clecoed the aft ribs onto the left wing spar. We went ahead and double checked the location of each rib to ensure we would attach them on the correct side of the attach angles. clecoed the aft stub spar assembly in place to help keep ribs lined up correctly. Taped off the holes that don't shouldn't be riveted until the wing skins are put on. Riveted the aft wing ribs onto the spar, not riveting the top holes on the wing or aft spar. Clecoed and match drilled the aft stub spar, then riveted the aft holes, the first 4 inboard with Lp4-4 rivets the rest with Lp4-3. Began deburring and fluting the forward ribs for next time.