Prior to the 1930s, think-piece was not a journalistic term of art, it was just someone’s mind or noggin: In a 1909 short story, the hero is bashed “over the think piece with a six-gun,” while a city editor in a 1910 story, impressed by a woman’s intelligence, exclaims, “Boy, your sweetheart must have a corking think-piece!” I have not found this meaning recorded in any dictionaries, though.
“How “Think Piece” Became a Pejorative Description " at