Ebay prices.....

oldhudsons

when I got the black '50 C8 conv. above (originally Corinthian Cream, a conv. only color in '50) the top had been replaced but the original owner had kept the back window from the original top which was rather large but with a piece of thick plastic connecting an upper & lower glass pieces that would flex when putting the top down. It came with the original tonneau cover. I believe that was the construction of the rear window ~