This could be an IBM screwdriver. IBM uses a number of proprietary screws, and refuses to sell the matching screwdrivers to anyone but licensed IBM technicians. It’s highly irritating, and I’ve been forced to break the case on more than one computer over the years as a result. The PS/2s were notorious for this, as they were designed to be completely proprietary.
(The floppy drives on the PS/2 model 25 were installed the wrong way; they were designed to sit vertically, but were installed horizontally, which means the drive head hung lower than spec, and would eventually catch on the disc and snap off. A proprietary PS/2 floppy drive was $250. A clone drive was $15. Because the pin-out configuration was proprietary, I hired a tech to make me an adaptor, which was cheaper than buying the proprietary drive from IBM. The tech eventually discovered that the only difference in the pin-out was that the sons of bitches at IBM had switched the power pin from one side to the other, which would be enough to blow out any ordinary drive you tried to plug in. And yes, it used proprietary screws on the case, too.)