The spelling of Sorenson's last name is different on the grave marker than in the official credits and closed captioning.
The real Ira Hayes was awarded the Parachutist Badge upon his completion of jump school, which he attended after his boot camp training. Later he earned the Presidential Unit Citation for his combat actions in the Pacific. Yet neither of these awards appear on his uniform after he returns to the United States for the war bond tour (however, his uniform does correctly include ribbons for the American Campaign Medal and the Asiatic-Pacific Campaign Medal.
The C-54 transport plane that flies Ira Hayes back to the United States has post-World War II U.S. Air Force star markings, even though the time is early 1945 (several months before the Pacific war ended).
When Ira reports to General Bridges after his disruptive behavior in Chicago, the shadow of a moving boom mic is visible on the wall above the window.
On Iwo Jima, Ira Hayes salutes his commander in a bunker located in the combat zone. Actual Marines do not salute in the front lines. In addition, Hayes drops his salute before his boss salutes him back.
Technical Sergeant Boyle, the war bond tour guide, wears no ribbons or service stripes on his uniform. But since he is an older Marine who has been in the Marine Corps for a long time, he should be wearing at least a few ribbons, plus one service stripe for each four years of Marine service.