Unfortunately no. The 360 version of Portal 2 does not come with a free copy of Portal 2. The same is for the PC (MAC) version. However, the PS3 version DOES come with a free copy of Portal 2 that you can either give to a friend, or keep it for yourself. Note that the free cpoy of Portal 2 can be given only to friends who own either owns a Mac, PC and/or PS3, along with a Steam account. If they do not have one, they can create one at:
https://store.steampowered.com/join/?
More info on this giveaway and Steamworks can be read here at:
http://blog.us.playstation.com/2011/04/13/valve-reveals-portal-2-for-playstation-3-steam-details/