A setback - During checkout of build steps for installation of wing ribs noted that the W-1210-L forward trimmed main ribs in steps 1-3 page 15-06 were installed on the wrong side of the attach angles (were installed on the outboard side of the attach angles and should be installed on the inboard side per plans). That’s why we check our work! Decided that it should be corrected so carefully removed LP4-3 rivets from each of the 5 ribs determined to be incorrect. All rivets were removed with no issues and inspection of holes showed they were all OK. Relocated to correct side (inboard) of attach angles and clecoed the riveted with LP4-3 rivets. Subsequently a check was made of the W-1208-L nose ribs and it was determined that they are also incorrect with respect to the attach angles. The two most inboard nose ribs are installed correctly per the plans – the remainder will have to be removed and changed.