​​​​​​Removing the lower bolt there appears to be oil in there. Looks like it's been weeping I guess. Anti seaze or RTV needed?

 

I have replaced several waterpumps on 98 and 99 XJs. I never put any extra sealant on the bolts. Made sure the surfaces were clean and used a gasket, There are all sorts of places for oil t leak in that area. If you are replacing the thermostat, make sure it stays in place while you tighten the thermostat housing bolts. It has a tendency to drop down after you put it in place. I use a tiny bit of RTV to hold it in place.

 

there should be no active oil passages near the water pump. It might be leaking/spraying from the timing cover gasket directly below but there is nothing oily in the bolt holes of the water pump It also might be spraying from the main crank seal and being splattered by the balancer