You're talking about the metal, silver colored, ones that cover the chips right?
Those are called EMI shields and they can SUCK to get off. I wasnt part of this particular tear down but here's what I know about EMI shield removal...
Try to look closely at the shields (yours and our pictures) and note that there are kind of two parts. There's what I'll call the "shield" and a part I'll call the "frame". The shield is basically a thin metal sheet that is typically crimped onto the frame. So to remove that bit all you need is a spudger or spudger-like device and some patience to peel it off the frame. If you wanted to remove the frame, prepare for "fun". If you are down to the frame note that the frame is actually soldered to the board. You will need to heat up the frame with a soldering iron to the point where the attachments de-solder. While the attachment point is liquified you will need to VERY carefully peel up that particular portion of the frame. Be careful not to use any small sensitive ICs as a brace. You could damage them or snap them off. You will need to go around the frame de-soldering and lifting until you can pull the frame off the board.
Good luck and be patient with it!