It's implied though. It's the point of Oda linking the cover story of Pudding getting captured(only one who can read Road Poneglyphs) on Blackbeard's ship with the current battle with Law over the poneglyphs. Law's reply to Blackbeard's about poneglyphs was even the fact that "winner takes all"
So obviously Blackbeard also got at least one Road Poneglyph copy in the meanwhile