Can't get the link to bring up the correct topic :-/
What ever it is (I can't tell) If someone's got them to fit an '02 bike they'll also fit a '98 bike.
There are a few options for aftermarket rear shocks for the old Fazer 600, Ohlins ones turn up occasionally on e-bay, probably better looking for a Maxton unit though. The original is shit, don't bother buying an OE replacement.