Col. Potter doesn't believe Klinger about Miller firing his carbine at non-existent gliders. He would have heard the shots.
While Charles would certainly remember the name of a beautiful young up and coming actress that he'd had dinner with, Hawkeye and BJ wouldn't have been likely to have heard of Audrey Hepburn. Her first major film that brought her to national prominence was released after the Korean War.
When Klinger relieves Miller, Miller attempts to chamber a round in his rifle, but the bolt locks open when he pulls it back, indicating that the magazine is empty.
While the three surgeons are boasting to each other who they have dated, Charles claims to have dined with Audrey Hepburn. She had gained no prominence in the U.S. until Roman Holiday (1953), which was released in 1953, after the Korean War.
The muzzle flashes from Miller's rifle when he is shooting at the various gliders don't match the shots heard. More shots are heard than muzzle flashes in both incidents.
It's after 1 a.m. when loony Cpl. Miller starts shooting his rifle at planes that don't exist. Many people come running out of their tents and, instead of taking cover, run right toward Miller while he is still firing. Col. Potter doesn't show up to see what's going on.