My take is either the goo or the adhesive is just there to hold the gasket in place till you install the pieces tighten the bolts. If it's a proper gasket it will seal without any goo.
As far as which side goes up, strictly your choice, but I'd usually stick the gasket on the part that's facing up.
A thermostat housing isn't something you'd normally try and reuse a gasket on, like a valve cover.


Kevin
1951 Chevy 3100 work truck
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.