I would like to add; That you may need some thermal past as there is a heat sink that splits in two when you remove the bottom.

The screw fixing points on my MBP came away from the back case. They are spot welded to the back case and in the Photo's I have you can see the point's each. You may think that if this happens you lose the ability to use the screws to secure the enclosure but you still can use the screws if you position the fixing points before clipping the front panel in place. Have a needle of small nail to align though the holes before replacing the screws. This is not easy and you need to be practices at this sort of repair.

They sit under the plastic surround and do! add the the string of the completed enclosure.

The screw fixing points on my MBP came away from the back case. They are spot welded to the back case and in the Photo's I have you can see the point's each. You may think that if this happens you lose the ability to use the screws to secure the enclosure but you still can use the screws if you position the fixing points before clipping the front panel in place. Have a needle of small nail to align though the holes before replacing the screws. This is not easy and you need to be practices at this sort of repair.

They sit under the plastic surround and do! add the the string of the completed enclosure.