When Corky is first sent into the FBI building he is questioned by the security at the door corky shows him his badge and then goes inside talks to some agents gets scared and runs out then he runs back in and the security who saw his badge with the fake name earlier calls him CORKY
His fake name IS Corky. Go to the scene where Corky is translating for the two foreign guys. Right afterwords, the two F.B.I agents are complimenting him on his tactics. The one man says "We'll back you up anytime, Pissant." (or something like that.) Kattan then says, "Call me Corky."