Saul Goodman wants the money order for his services to Badger made out to a fictional "Ice Station Zebra Associates," the same name he and Kim Wexler gave their fictitious software company in their second scam in the second season of the spin-off series, Better Call Saul (2015).
When Walt and Jesse threaten Saul out in the desert wearing ski-masks and holding guns to Saul's face beside a shallow grave, Saul says to Jesse "Take the ski-mask off, I feel like I'm talking to the Weather Underground here." Weather Underground was an American radical left-wing militant organization formed in 1969 that issued major bombing campaigns against numerous American Federal facilities in protest of the Vietnam War.
The crawler text during the Better Call Saul TV commercial reads, "Not actual clients, paid actors representing testimonials, affidavits on file - ¡Se habla espanol!"
In Saul's office, Walt is wearing an Albuquerque Isotopes hat. The Isotopes are a minor league baseball team and, in chemistry, two or more substances with the same chemical makeup but different atomic structures.