At the end of the episode, Castle refers to the blue diamond, a fake diamond necklace, as the stuff that dreams are made of. This is the same line that Humphrey Bogart improvised when describing the fake black bird at the end of The Maltese Falcon.
Jack's love interest is named Vera. In the Firefly episode "Our Mrs. Reynolds," it's revealed that Jayne Cobb, one of the main characters, refers to his favorite gun as "Vera."