So, what I think is that Backes just pulled it from out his ass. I think he's not providing the source because he doesn't have one. I think he just made it up. In a word: he lied.
It's highly unlikely that Richard Sprague examined the original Altgens photo. Why would the AP go along with that? Were they going to accommodate every researcher and journalist who wanted to see it? Why should they?
Today, they sell copies of the Altgens photo, and I bought one. I don't know if they did that then, but it was certainly more practical than allowing every Tom, Dick, and Harry to see it.
Provide the source of your statement, Backes; otherwise, be marked as the liar that you are.