In episode 3-22: The Staircase Implementation, Leonard is telling Penny the story of how he and Sheldon became roommates. During one scene, Sheldon shows Leonard the apartment flag, "a golden lion rampant on a field of azure". In this episode, the ID card that Sheldon gives Raj has the same design as the flag.
When Sheldon mentions "an eye for an eye" from the Hammurabi Code, he is not quoting the Bible (although the phrase does appear in St. Matthew's Gospel) but the legal code of King Hammurabi, ruler of Babylon in the first half of the eighteenth century B.C.
In The Hot Troll Deviation, Raj revealed he has 3 brothers and 2 sisters. In this episode, Priya confirms that she has 5 brothers and sisters. She doesn't break them down by the number of each, but the total number lines up as 5. She would have 4 brothers and one sister.