The game’s not even out yet, but that’s not stoping Activision from releasing the “Guitar Hero III: Legends of Rock Companion Pack.”

It’s basically a soundtrack CD with songs from the game, but it comes with three previously unreleased expansion songs for people using the Xbox 360 to play “GH III.” You’ll have to use a unique code (included with the pack) and Interscope’s Guitar Hero site to get the Xbox Live code to download the songs, which are expected to be available on Oct. 28.

What can you look forward to getting? AFI’s “Carcinogen Crush” (off an EP due in December), Flyleaf’s “Tina” and a remix of Marilyn Manson’s “Putting Holes in Happiness” created by the Yeah Yeah Yeah’s Nick Zinner (oh joooooy, Manson gets hipsterized!).

The companion pack is out on Oct. 23 – six days before the game actually comes out.

The full track listing is after the jump. -AFI’s “Miss Murder”

-Sonic Youth’s “Kool Thing”

-Queens Of The Stone Age’s “3’s And 7’s”

-Smashing Pumpkins’ “Cherub Rock”

-Velvet Revolver’s “Slither”

-Living Colour’s “Cult Of Personality”

-Rise Against’s “Prayer Of The Refugee”

-Steve Ouimette’s GH rendition of “Devil Went Down To Georgia”

-GH intro by Slash

-Flyleaf’s “Tina”

-Marilyn Manson’s “Putting Holes in Happiness” (remixed by Nick Zinner)