Weird as hell, though the fact that it shows up almost exclusively in the post WWII and pre-Vietnam era suggests that Cooper absolutely had to have picked it up overseas during WWII. Which is the opposite of a shocker since I would be completely floored if he hadn't served at that time.
I think there would have been a good sized chunk of the male population who would have read the 1958 baseball article and immediately recognized the phrase for what it was and not been puzzled by it; in that way it's "regular."