They can be removed sucessfully.
I took a set off a 69 Nova with absolutely NO damage.
You have to be VERY patient...slow,and easy.
The quarter window pieces are pretty easy. The longer angled piece is secured with screws under the window channel, and the short vertical piece is clipped on.
The door trim is similar to drip rail mouldings...
Remove the vertical piece first.
The hardest part is getting it started. Start at one end, and very carefully work your way around the frame.
They are anodized aluminum...the anodize can be removed, and the aluminum polished to a brilliant shine, but they must be polished ocasionally to keep them looking nice.
I sure there are places that can restore them $$$$$