Do you treasure your prized Elvis autograph or signed picture of the Beatles? You might want to double check—memorabilia authenticators PSA/DNA announced on Thursday that over half of those artists' signatures for sale in 2012 were certified as genuine. Among others on the list are John F. Kennedy and Michael Jackson. Neil Armstrong jumped to No. 3 after his death in July, when the number of purported autographs by the late astronaut skyrocketed. But Armstrong was "very conscious" about giving away his signature—meaning that the signed moon rock you have is probably also fake. Sorry.