I don't believe that this is as much of an issue as some are making it out to be. Yes, for certain, new windscreens on new cars are glued or bonded to the car. However, a true, professional automotive glass place will be able to do it. If in the oft-chance it may be some new franchise, or a new operation with no skilled workers, that may be an issue. In Michigan where I used to live, there was a local place called Henderson Glass (which had numerous locations throughout Michigan) that could do it. Most skilled body shops can do it as well. The glass on my Pagoda was changed by Motorwerks, and the guys that did it are all younger than all of us, and all considerably younger than the cars. No big deal; they fix and do all kinds of work on all kinds of cars from all eras 1950s+, so this is and was not an issue for this independent repair shop. The easiest thing to do is just start calling around.
Now--the rear quarter glass on the hard top? That's a different story. That takes not only experience, but specific skills and tricks. Still, this was done on my hard top by the young ones, but they have gleaned their experience from other pros coming in their shop as well as numerous other hard tops being restored. All the rubber on my hard top was changed, and all the trim re-plated; so all the glass was removed, and all the glass was replaced with new OEM seals.
The glass on the hard top and doors is all OEM, and features the mark/brand "Kinonglas-Kristall"; that's all 50+ years old. The replacement windscreen, new, says "AGP" which is a newer glass company supplier. All glass on my car now has the Mercedes-Benz three point star on it.