No they ain't all the same. They change from the older coarse ones (M3 x 0.60) to the new standard metric M3 x 0.50 at about 140.000 when they loose the nicer double scroll trim rings.
By chance, I tried a late model Mk VI bari (200xxx) pivot screw on a 5 digit VI tenor and it fits. So maybe this is not cast in stone? BTW, anybody knows where I can get some of these early pivot screws?