I like that they are offering a 100% guarantee, but I'm not convinced this is period. That's a 'Bain News Service' stamp, which is not "ironclad" proof of type I by any means - 'Bain News Service' frequently copied old photos, some from the 1800's. Does this photo really 'look' 1916 vintage to you all?
Just wondering - I'm sure with a guarantee such as the one below, if the winning bidder didn't feel good about it, it would be no issue to return it.
1916 Red Sox team photo with Ruth
"...prestigious “George Grantham Bain” and “Culver Pictures, Inc.” credit stamps for ironclad authenticity relating to its Type I Original Photo status. In fact, had we not received this image right before our consignment deadline, we would have sent it to PSA for Henry Yee’s official Type I cert. However, we 100% guarantee its irrefutable “Type I” status, and if the winning bidder chooses, we will gladly have the image certified by PSA after the auction."