It very well could have just been Torx back then. I remember opening my original 128k Mac in '85 or so to do the 512K memory upgrade, and a weird specialized screwdriver (Torx) was required to open the case.
And n64 cartridges and cases. And snes too I think.
Another trick is to melt a plastic pen with a lighter and stick it on the screw and wait for it to cool.
