When the American flag is seen flying at 30:24, it is clearly a 50-star flag (the 48-star flag had even rows). The scene, however, is during the period that Philby was assigned to Washington, DC., in 1949.
General Walter Bedell Smith is harassing James Jesus Angleton at CIA headquarters about information that Angleton has about the Cambridge Spies. The aggressive and impatient Smith blurts out, "Come on Angleton! Where's the beef!" This phrase actually originated in a television commercial for Wendy's chain of hamburger restaurants in 1984, more than 30 years after the year in which the scene is set.