Wal-Mart swaps out discs with no questions asked. As long as it's for the same game, you'll have no problem getting a replacement for LRB.
And when you do, open the box, look for the insert, and there's your code.
[ ] U2 [ ] Sheryl Crow [ ] Cracker [ ] Springsteen [ ]The Pogues
[ ] Cage the Elephant [ ] Neil Young [ ] P-Funk [ ] Heart [X]RUN-DMC [X] MeatLoaf