RobertH - Your boat is quite a bit newer than mine and I am not familiar with your windows. On mine the side windows are glass and replacing the "kitty fur" slide track was not hard, the rubber trim around the edge that covers the screws was easy to replace too. I can not remember for sure if once I removed the track the glass could come out of the frame or not, I think not. IIRC it did not but I was able to pull the new track in with the window in the frame using needle nose pliers. While they were apart I also put new screen in too. Just have a nice flat padded work surface and you are good to go. The front might be more more problematic as mine were plexy and the old plastic was a bear to remove. Grady stuck the plexy in with some very goowey black stuff that was very hard to remove. If yours is similar the old glass amy come out in pieces. I replaced the plexy with a draker tint and that is nice from the inside and out. As an experiment I had the front frames powder coated white while they were out, they are holding up pretty well and that was about five season ago. Rehabing the windows was well worth the effort, the leaks stopped and my cabin is dry now. If your boat is covered the project is a good winter one and does not take very long. Perhaps there is someone here with your vintage windows that has completed the project. Mine was a straight foward DIY poject. The material from marine glass was the same as OEM so there was no adapting to be done which is always a plus.
Good luck with your project.