The hood insert is made of some form of fiberglass - it is not metal. It is VERY easy for the drian holes to clog which could be why you are seeing rust - as water has become trapped under the insert. Not a very good design really, as you will see that the hood insert can trap a small amount of water even with the drain holes open. If you open your hood and look in the front corners, you'll see two plastic tubes that look like fish tank air line. Those are your drains. It's a good idea to disconnect them and blow air through them regularly to keep them cleaned out. If water pools at the front corners when it rains or when you wash it - they are clogged.
"If you're not living on the edge --- you're taking up too much space!!"