I have it in my inventory as a gift, but I couldn't redeem it because it was region locked. I got it from someone (from the forums here I think?) that couldn't use it in their country, and I can't use it in the US. Was just going to toss it but decided to contact Steam support, and after I bit of a fight with them because they thought I was trying to get them to break the region lock to claim it, they said it is region locked to South America market. I am opening this with the SA region lock selected.

Pic from the steam support site >> http://i.imgur.com/av3mmAL.png <<

If you are in what Steam considers South America (TIL Mexico is South America ... LOL) ... good luck. And hopefully the Steam Support guy wasn't yanking my chain and told me the truth about the region ...