you have to be specific...pictures help
Sounds like you caught Andy at the end of a bad day. He is usually as straight forward as you can get.
You must be talking about the end windows. They are curved. The side windows are flat. The curved ones came as "plexiglass"...the replacements that you have to make....repeat YOU have to make, should be out of SR Lexan. We discussed this on your other post. The side , flat, windows should be made of a tempered glass. Any glass shop will help you there. Watch the thickness.
"If it can't be reduced, reused, repaired, rebuilt, refurbished, refinished, resold, recycled or composted
then it should be restricted, redesigned or removed from production."