When I bought my car the glass tops were originals that were cracked and unmatched, but usable. I later shattered them putting them in the back. I then found 2 sets on Ebay that had one good and one broken on opposite sides. They almost matched but I shattered one of them replacing the weather stripping. After this, I swore to do the Corvette community the favor of never touching original glass tops again.
It seems that no one can make original replacements because the glass contained hazardous stuff. The original ones still out there are becoming more and more rare (thanks to people like me). Also, the originals fade in color from dark blue to aqua to amber with sun exposure, so unless a set has been together from the start, they do not match. There are black and lexan replacements, but they look cheap to me. There is a company that makes a one peice top, but that seems strange. I found a company that specialized in collecting and matching original tops, but the price was sobering. In the end, the solution for me was a set of original fiberglass tops off Ebay. I was patient and actually found a set that was my original color and got them cheap. I replaced the weather stripping and dyed the interior panels to match. Here in Florida, the glass tops just intensified the r134 A/C problem, and the fiberglass is so much more durable and lighter, I have been very happy with the change.
God bless, Sensei