I had one in a fiberglass halfcab top. I sold the top and never even thought about pulling it out until it was too late. I'm fairly sure they guy who bought the top was not going to use it or would not appreciate it. It was scratched, but could have likely been polished out, or at least could have been used as a pattern to form new ones.
The rear window in my Balloon Chaser F100 is also a plexi bubble like this.
I have tried to find some of the other plexi windows that were used on the Balloon Chaser van which I am wanting to re-create and it seems that these do not meet current DOT requirements and are no longer produced. At leas that is what I read somewhere while researching trying to locate some.
The plexi gull wind tops on the F-100 and Ambulance Bronco have a molded in airfoil shape. I have searched to find some for spares, but have never found any. I will have to likely have to thermoform those myself if I ever need to replace one.