Just did my 03 thermostat and it doesn't use the paper gasket--just the taper o-ring which crushes and seals the thermostat housing as well as keeps coolant from going past the thermostat. I think my 98 was that was but I insisted on using a paper gasket and the dealer gave me one. I believe it had a paper gasket or some kind of material between the metal parts.

Yeah, mine uses the rubber o-ring with the groove.
The housing had no gasket, and I didn't put one on. It has never really leaked anything from the housing. (but I guess you could use a housing gasket?)

ALSO, don't expect the guy behind the counter to know much about what you need, cause for the 1992-1999, they have listed the old paper gasket.

You're right about the counter. I went to 4 different stores looking for the paper gasket for my 03... they all showed part number but NOBODY stocked the part. I was for 92-04. It'* not needed I figured out after I took apart the housing and found no gasket.

Can anyone verify that their 98 had a gasket material besides the rubber ring? I recall my 98 had something there-maybe a silicon sealant or something from the factory. I put a paper gasket on it but that was a while ago.