If I remember correctly, he was on the cover of a muscle and fitness with the quote that stronger boxers, make better boxers and weightlifting is the key.
I think Wieder played fast and loose with facts. And certainly with quotes.
It's probably the nature of a magazine/publishing industry where ghost written articles were so common. Attributing this or that to a particular person. For example writing about Sergio Oliva's shoulder routine and Sergio always does X exercise, then years later in an actual one on one interview for another publication Sergio says he's never done X exercise.
I'd be willing to bet money that Muhammad Ali never, ever, said anything about weight lifting making a better boxer.
I remember an article in M&F about Bruce Lee that included a receipt for dumbells purchased by Lee and a caption implying Joe may have trained Bruce. LOL!