Should re-installed fasteners be oiled?

[san rensho]

I am of the school that all fasteners should be perfectly clean, all threads chased and lightly lubricated with oil. I've followed this for years and never had a fastener strip, fall out or a component leak or come loose using this method.

However, Porsche torque specs call for dry fasteners unless it specifically says to lubricate them. But, all the Porsche fasteners I take off my car are coated with a greenish blue coating, which is some sort of anti-corrosion compound, but wouldn't this compound also be a lubricant?

So does it make sense when re-installing a fastener after its been cleaned, to oil the threads and use the Porsche spec, since the new Porsche fasteners were lubricated to begin with?