Re: I've always wanted to know
Even an undergrad student who's done a little chip-design work in class can often recognize some common structures in relatively simple architectures - things like barrel shifters (note the one in the ARM1 picture in the article). I remember looking at chip layouts with friends in the CS and EE programs, guessing what various sections were.
Someone with more experience can no doubt do better.
But it's just large-scale stuff. It's like looking at an aerial shot of a city: you can say, oh, here's a park, and here's a high-rise office district, and this is a residential neighborhood. But you can't read the street signs without getting a closer look.