Hi Brad, I see no one has answered your request unless they sent you an email, I have been having a massive clear out after just selling my 37 Buick convertible and I have come across the original side glass from my 41 Cadillac convertible I restored some 15 years back, its all broken but still held by the plastic, the main shape is there. Too heavy to send to you of coarse but I could take a pattern if no one else has responded to you. Also found the two original frames, quite rusty in one spot as they all are. I had 4 new ones made out of brass channel, two I used on the car and two kept as spares as the curved shape is much the same on all my GM convertibles. I have seen these on ebay in recent times.
