This car has a 2 piece style top from the factory. You can buy a top with window as a complete outside cover, or you can just buy the top only section or window only section as needed.
This convertible top for the Buick Gran Sport (GS-GS400-GS455), Skylark & Special fits the 1968, 1969, 1970, 1971 and 1972 model years.
These guys stand behind the products they sell. Ordered a top almost 3 years ago from TopsOnline.com and the other day I noticed a seam coming apart, sent them a couple pics and I had a new top sitting at my door in less than a week. No hassle customer service is rare these days. Thanks again for taking care of your customers!- Eric Woollums