Although viewers of the show were told Dan's real name back in season 3, this is the first time that the characters on the show learn that it's Reinhold.
Joy tells Bull that he resembles "a Cro-Magnon man". In an episode from season 4, Author, Author (1986), a depressed Bull was found by Harry in a museum, sitting next to a bust of a Cro-Magnon man among other prehistoric humanoids.