I put some speakers in the footwells of my '72 hardtop Cutlass, and in the process removed the interior metal covers over the windshield pillars. I found a bunch of pieces of plastic, as in the picture below. I think figured out where two of them were, from where the screw holes are. But I wonder if originally they were all one piece? Are they for noise attenuation? Are replacements available? They are green, like my interior. Thanks.