The reveal moulding next to the window glass is stainless and it is often rusted under there (sometimes badly). They are not reproduced and good used are pricey. They are held on by clips, slide off and can be very difficult to remove. Easy piece to damage. There is also a hidden screw or two obscured by the scrapers. Take your time with those!
If you are speaking of the thin peak moulding, it is clear anodized and is supposed to be popped off from the inside (a pain). It is reproduced, but other than the door piece, the reproduction is poor. Good used are not terribly difficult to find.
There are guys who will restore your reveal molding and make it look better than it did new. Just be careful not to damage it taking it off. I had the reveal molding reworked on my car. Can't remember just how it came off but I managed to do it so it can't be too hard.