A big part of what Chipworks does (as a company) is reverse engineering silicon from die shots and x-rays and such. They're not just going to hand this kind of information out on a platter - they were commissioned to do a cursory glance for this puff piece.
But it also doesn't take a genius to guess at what the various hardware modules do just given what the iPhone can do.
But it also doesn't take a genius to guess at what the various hardware modules do just given what the iPhone can do.