This article reminded me that the Sands of Iwo Jima included several actual Marines. Here is the section from Wikipedia.
Rene Gagnon, Ira Hayes, and John Bradley, (until 2016, Bradley was incorrectly identified as being a flag-raiser) the three survivors of the five Marines and one Navy corpsman who were credited with raising the second flag on Mount Suribachi during the actual battle, appear briefly in the film just prior to the re-enactment. Hayes was also the subject of a film biography, The Outsider, and Bradley the subject of a book by his son James, Flags of Our Fathers.
Also appearing as themselves are 1st Lt. Harold Schrier, who led the flag-raising patrol up Mount Suribachi on Iwo Jima and helped raise the first flag, Col. David M. Shoup, later Commandant of the Marine Corps and recipient of the Medal of Honor at Tarawa, and Lt. Col. Henry P. “Jim” Crowe, commander of the 2nd Battalion 8th Marines at Tarawa, where he earned the U.S. Navy Cross.[4][5]
Audie Murphy played himself as well.