Those shields cover up the top cowl, to side cowl seam. This was gm s fix for water leaks back in the day. When the cars were transported to the dealer, the drivers often tied the cars down too tight breaking the seam and seam sealer. I repaired many cowl water leaks.. gm came up with this band aid The plastic covered up this area, and diverted water away from this seam.. btw sorry do not know who may re-pop those covers..