Last week, this series stirred up controversy by presenting a segment about a guitar that may or may not have been owned by Bob Dylan, and played the night he “went electric.” This week, the show investigates another controversial find – but this time the controversy is over history, not provenance. It’s a 78 r.p.m. record (kids, ask your grandparents to explain both “78 r.p.m.” and “record”) from the KKK label – and yes, that label stands for records pressed and distributed by the Ku Klux Klan. Check local listings.