But at the time, the entire case industry was moving forward with producing cases. They weren't just prototypes, you could actually buy the "iPhone 5" cases. It would have been impossible not to report on the cases and what they represent.
I believe and have been told that the iPhone 5 design was real -- just not ready.
As for mockups. Both sides tend to point and say, oh - look what they got wrong. or look what they got right.
Here's our assistant rendition: http://www.macrumors.com/2011/09/30/a-look-at-apples-assista... which was pretty spot on.
But the thing about rumors is it's like a statistical distribution. You can't take any one rumor and say "oh, this is it". Eventually, by the time the event happens, the rumors settle around something that frequently is very close to the truth. See, our Rumor Roundup right before the event for the final conclusion from months of rumors: http://www.macrumors.com/2011/10/03/lets-talk-iphone-rumor-r...