Well there's still a chance it could be the wrong one. The one for the MK3 is different to the more widely available one for the MK4 though both are unavailable from Lexus. There are also two different alternators listed for the MK3, one rated at 80A and one rated at 100A. The 100A was also revised during production but the part number for the substitute went down rather than up which I'm told is unusual. On top of all that, suppliers ask me for my registration first which never brings up anything because my car spent so long in the Isle of Man it lost its original reg and had a period one issued.
As you can see I've learned a lot about alternators in the last couple of days!