Sheldon says that he and Leonard have a combined IQ of 360, which is a call-back to Pilot (2007) when they were having problems getting into Kurt's (Penny's ex-boyfriend) apartment building.
Title reference: Sheldon and Leonard's efforts in trying to get the Athenaeum Club booked for the Shamy wedding.
Just like Mrs. Wolowitz and his big sister Halley, Neil Michael Wolowitz is mostly heard but only rarely seen on-screen in the remainder of the series.
This episode was taped exactly eleven years after the pilot episode was taped.
Sheldon finds out that Leonard hasn't been truthful to him, and openly wonders if he can ever fully trust him again. The same happened in The Deception Verification (2013), and Leonard had to make up by taking him to the barber, the dentist and the Los Angeles Bureau of Weights and Measures. Here, he does by helping him secure his wedding location.