Good question there.
Size wise, I believe they are the same, it's just how they attach that is the difference. The back-up light letters are glued on, I believe they are plastic too. The hood letters have studs on them, so you have to drill holes in the hood. They are definitely metal. Since your hood has the black-out treatment, it would be mighty hard to glue the letters on without having the glue show around the letters. It might be worth a try though.
Mike