What Pontiac did do at the factory is add a thick insulating liner to the convertible well material to some 1st Gens.

To date, I have not found a repro replacement for that liner. I have spent hours and numerous inquiries to convertible top specialty vendors trying to find a suitable replacement material.

Also, I can find no documentation that shows which cars got that extra insulation other than in the 1968 Pontiac Sales Manual page Q-2. In a section describing "Special Acoustical Features.", they state: "Certain 1968 models have added acoustical features to enhance ride, comfort and quietness.".......and...... Convertible also have a heavy cotton-fiber lining in the top storage well to muffle out noise in that area."


That liner was very fragile. As mine crumbled into the trunk during the daily driver years, I finally pulled it off the thin liner and discarded it.