Fanmail.biz

I received this in the mail today. It was just a plain index card with this signature. All it said was that it was from "Santa Clarita, CA 913." Underneath it, it said "15 JUN 2013 PM6L." I can't make head or tail out of who it could be. Help!

http://s1148.photobucket.com/user/ajlpo ... 4.jpg.html

After some searching, I think that this is Slash from Guns N' Roses.