Maybe the a/c in the old pic is G or F -6? That would explain the smallish cowling bulges. IMO the MG131 bulges are a quite pronounced difference between A6 and A7 and that is not very evident in that pic.
I don't know what kind of cowling they used for G models which lacked the MG armament. Was it normal MG171 cowling with gun ports faired shut, or did it depend of what variant the G conversion was made of?
-C+