Guys I think this is a 4x5. I received a message from someone with a 5x7 who measured theirs and it was 8 1/8 inches square. that's like over an inch bigger than the film size. The same pattern is here. 5 inches plus 1 and a half inches.. makes sense. This is a 4x5 camera!
Cool! I'm foiled again in my 5x7 quest, but...cool!