Either way, this is a pointless argument/analysis as its impossible to tell without being able to physically put a few iPhones from different batches together to get a real physical comparison.
Here's another way to slice it (literally). Flipped half the image. Left the guidelines on this one as well.
I agree that this is no substitute for measuring the actual phone, but, at least in that photo, they are identical. Certainly not off by 1mm as the original post states.