No I don't think they are coated with anything. I painted mine with plastikote - although for our previous Syrian I didn't bother and he didn't pee on them - but they can get water mark stains from bottle drips etc. Now I have a granite tile on the shelf under the water bottle so that soaks up any drips
I also had some hemp mat on one shelf which probably gave it some protection. It's probably a good idea to protect them somehow as you can't get replacement shelves.