While doing some unrelated research, I found this Paul Lukas column from 2008. I had heard that Killebrew was the inspiration for the MLB logo before, though I didn’t realize it had reached “controversy” status. Here is the logo:
…and here is the inverted drawing of Killebrew from the 1963 program:
Looks pretty similar, but as Lukas pointed out, so do dozens of other baseball players. It sounds as though the true story is that Killebrew is one of many images the artist used as a composite for the logo, but I think it is a much better story to simply say that Harmon Killebrew is the Major League Baseball logo.