So I've been missing a screw in the top left for probably two years now and I want to replace it with a new screw some time before I sell the Macbook. My concern is the apparent different configuration, numbers, and sizes of the screws. I have a Late 2008 aluminum Unibody Macbook "A1278" 2GHz MB466LL/A Macbook 5,1. According to ifixit, the screw configuration is different between my "A1278" Macbook and the rest of the A1278 Macbook Pros. This ifixit page for my computer notes a single 3mm screw in the top left corner that is different than the four 3.5mm screws along the bottom. There are also three 13.5mm screws along the top to the right of the 3mm screw. I'm missing the single 3mm screw. Unfortunately I'm having trouble finding a complete set with the 3mm screw, 3.5mm screws, and 13.5mm screws. What I've seen are the 10 necessary for the MBPs (7 3mm and 3 13.5mm). Either way I guess I'll end up paying $2 for a set of MBP screws which would obviously contain the 3mm screw I would need and just store the rest for next time I lose a screw.