When Castle shows up at the apartment of the dead man, Castle picks up a Dancing Hula Girl dashboard figurine. Its the same one that was on the Control Command Panel on the Firefly commanded by Hoban 'Wash' Washburne (Alan Tudyk) and captained by Malcolm 'Mal' Reynolds (Nathan Fillion).
Caleb Brown's alias Peter McCaffrey is a mash-up of the principal characters in White Collar (2009) - Peter Burke and Neal Caffrey
Alan's love interest in the episode is named "Gwen Parker". Her name is a mashup of Spider-Man's Peter Parker and his first love interest, Gwen Stacy.
Jonathan Silverman starred in the movie, "Weekend at Bernie's", which is about two friends who spend two days trying to keep everyone convinced that their mob-murdered boss is still alive. Their effort works well enough to confuse the increasingly-stressed hit man, who can't understand why Bernie won't die. At the same time, Silverman's character is pursuing a woman named "Gwen".
Aired on Stana Katic's first wedding anniversary. Though they weren't married at the time, her husband Kris made a cameo in season five's "Death Gone Crazy (2013)".