Slim Pickens character would be far more likely to identify John Wayne as a Hollywood Star than either Clark Gable or Gary Cooper (who he probably thought of as Kansas City fggts

Something to remember, Eric, is that many of the people fighting the war at that time, grew up watching John Wayne (among others) a decade before, in Saturday matinee's at their local theatres.
It would be a natural assumption that these people would not only be aware of John Wayne, but already consider him "iconic", having witnessed his exploits on (literally) a weekly basis, when they were of a more impressionable age.
On top of that, Wayne had already filmed John Ford's vaunted blockbuster,
Stagecoach
, which made him an almost overnight international star.
By 1941, he could already be considered a major Movie Star to people of all ages.
and that goes for not only for Americans, but anyone in the world who grew up watching him at the movie theatre.like the Japanese we had just begun fighting.
Tell me, you love your country?
Well, I've just died for it.

B-movie actor or not, by 1941, he was a hugely popular star who represented the idealization of the American hero. At the time, he was not unlike the Chuck Norris of the day.
Originality needs a reboot.

He had been in countless westerns in the 30's but he was hardly an icon. These were B-Westerns for Saturday afternoon. Stagecoach put him on the road to stardom but it would take until the late 40's and early 50's before his status was established.

John Wayne already had been established as an American icon having starred in countless westerns in the 30's.
Originality needs a reboot.