Rear valance

I have a 72 Dart..And im putting back on the rear valance after being off for a few years. I have the 4 lil screws that hold the valance to the corners of the qtr. panels. But what was used for the 4 holes that are spaced along the middle of the valance. I dont have them and I was thinking its those rubber/vinyl push in insert like screws that hold it in. Any help please...DAN