They did change half-shafts at least once over the years, but all of the gen I and gen II half-shafts will evidently fit on any other gen I and gen II, UNLESS someone had an ABS car (2001/2002). If one has an ABS car, they could only use the ABS half-shafts if they want their ABS system to work, with the gear-looking ABS sensor wheel on the end.
However, as there may be a strength difference on the gen II half-shafts, you might want to stay with half-shafts from a gen II.