I understood your point. For historical accuracy, Duke looked way too old for the part. But Zanuck knew if he wanted this war movie to be successful, he had to have Duke in it. They seem to be more into accuracy in today's films than they did back in the day. Movies are roasted now, if they are not accurate to history. It didn't seem as important back then.
Posts from dukefan1 in thread „The Longest Day (1962)“
Darryl Zanuck wanted Duke for the part. He wanted him so bad, Duke drove up the price for the few days he filmed the roll. It was Duke's way of paying Zanuck back for comments Zanuck made about Duke producing and acting in The Alamo.
Here is an example of the book. It goes into alot more detail than the movie could. I recommend it as a very good read for war buffs. Enjoy!