Prior to filming, most of the principal cast joined a core group of 62 extras for boot camp, where they endured a week of rigorous military training as WWII Marines. The production received assistance from the Department of Defense, which made Kaneohe Marine Corps Base available for the actor's basic training. Under the tutelage of Sgt. Maj. James D. Dever (a retired 25-year veteran of the Marine Corps) and his active-duty Marine instructors, the cast learned how to walk, talk and think like Marines.
Weapons coordinator Robert 'Rock' Galotti amassed over 500 vintage WWII era firing weapons and 700 rubber replica weapons for the film from private collectors and prop houses. Also featured moving across battlefields are vintage Sherman tanks, their smaller Stuart brethren, and Japanese Hago tanks.
When the film release was pushed back, many of the posters/cutouts/promotional items/etc. sent to theatres were recalled. As such, they have become collector items and fetch huge prices on auction sites like eBay.
Steve J. Termath was originally cast for the role of Pvt. Nellie. However, the role went to Martin Henderson when Termath took a brief hiatus from acting for actual military service, enlisting in the US Army Reserves.
George Smith, one of the Navajo code talkers who helped the U.S. military outfox the Japanese during World War II by sending messages in their obscure language, has died, the president of the Navajo Nation said on 2 November 2012.