Here's the difference on the '63-6 vert W/S gasket

I don't think the quality or fit will be a problem at this point. Naturally, I won't know until I actually try to install everything. My main purpose was to answer the question as to why there was a different part number in the factory manual for the convertible seal verses the rest of the body styles. Since they only make one replacement seal for all body styles, it might be important for someone doing a 100% stock restoration. In that case, since they don't make an exact convertible repro, you would want to save the old gasket to reuse, even if you accidentally break the windshield to do it. The glass can be had, and proper codes etched into it to make it look original. Once installed, you might not see any difference between this replacement and an original except for that width different on the bottom inside section between the glass and the extra groove.