Wheel well moulding were a popular dealer add-on. If you have holes in the quarter/fenders, mouldings were installed at one time. The only way to tell if your car came with them from the factory is by looking at the build sheet.
I got mine from Tom at R/T Specialties. One was damaged in shipping and he sent me a replacement.
The best way to install them is to fit them to the car BEFORE paint. They can be a pain to install. If you already have holes for them, don't be surprised if you have to drill new holes.