Randy, totally agree, but do you mean silicone grease or silicone sealant? I use a wipe of petroleum jelly, which I recall is what Volvo calls for on top of the rubber mushroom gasket. Using something greasy (that doesn't affect rubber) allows movement under the head flange during final positioning swinging the pump up into place so the lip of the gasket doesn't stick and accidentally fold over. Like you, I'll also use a wipe on the block side of the main gasket to allow later positioning without damaging the gasket, also on the return line rubber collar, but I don't recall that Volvo called for either. This shouldn't be needed on a nice clean surface, but I usually do it anyway.

A comment I made to Bill earlier is running a bead of RTV around the outside of the mushroom gasket lip. It's not for sealing the gasket, but rather for providing protection from oily grunge (weaping valve cover gasket and oil spills when filling) getting into the crack below the head flange and slowly ruining the rubber gasket, making it gummy and prone to leaking. When the pump is forced up for final tightening (I pry it up) the RTV will ooze out the side and the excess easily wiped or scraped off. The small amount doesn't make pump removal any more difficult next time and there's minimal extra cleanup as long as it doesn't get forced into the grooves. It's a useful trick one of the old pros recommended here years ago. Probably more important if you're using a cheap aftermarket gasket set with inferior rubber compounds rather than the Volvo rubber, the Hepu gaskets also likely being good quality.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now