I can understand what you are doing as work can be un-done without too much difficulty (unless you install window plugs as well?).
Sure the subject car can be un-done, yet with much work, likely won't.
Keep in mind this car was a low mileage (unrestored?) car prior to ths work.
I would be nice if the shop photographed and documented the car on it's disassembly. This, keeping in mind they're origial only once.
I wonder how other racers feel about the conversion?