Painting the cab interior this week, I have purchased a headliner from Chevy duty, I also got the center bow, It was missing the headliner,rear bow or trim retainer, however I can't figure out the front fastening I see screw holes for a rear trim bow. Does it just go over the front upper windshield support which the sunvisors secure to? Don't see any screw holes etc. on front. I see American Classic has a used front and rear listed haven't a clue. Zeke