I just got sent a code for the escalation map pack for free..Is it a scam?

I own a PS3..A friend I have added (I have no idea who he is just someone who sent me a request a long time ago and I accepted) sent me a code saying send this to all of your friends and then go to the psn and type this in to receive your free escalation map pack..Im havent done it yet because I dont want it to be a virus or something and have my ps3 screw up..Does anyone know if this is legit..or is it a scam..cause if its a scam Ill just go buy it myself?..Thanks for any help anyone can offer..I appreciate it.