Ok, im pretty sure its the wrong name, but i know on my 92fs is plastic.  I saw here about a month ago or more someone posted a website selling metal ones.  Since i just bought my beretta, and pick it up tuesday, i kinda want to order one so i can get it changed as soon as possible.  

www.langdontactical.com

As Lumpy mentioned, Ernest sells metal guide rods, including a solid guide rod that adds some weight up front.

I believe you can also order the metal guide rods from Beretta, and most parts houses like Numrich should have them.

But the real question is why do you want to change it out?  The polymer guide rod is self lubricating and it will always be black no matter how badly it might get scratched, unlike the metal rods.