SOURCE: Epitaph RAT BOY first found Armstrong’s punk/hip-hop band The Transplants in his father’s record collection, and subsequently delved into his back catalogue with Rancid and Operation Ivy. RATBOY had repeatedly mentioned his admiration of Armstrong in interviews, which led to the L.A. punk veteran discovering the young Essex upstart. Separated by 30 years of age and the Atlantic Ocean, RAT BOY and Armstrong sound like the very definition of an odd couple. But they…