Spark plugs wet with oil above or below the threads?

Below the threads:
It can't have anything to do with the VC gasket. It's gotta be rings or valve seals or something internal.

Above the threads:
I don't know about D-engines, but some (F-engines?) have another seal farther down in the spark plug tube. Sorta like the cam cap itself is part of the tube, and there's an o-ring between the cam cap & the head itself. Is yours like that??

Compression test:
Warmed-up engine, all plugs removed, spark & fuel disabled, wide-open throttle. Crank enough times for the pressure to get as high as it gets & stops climbing. I guess that's usually 6 or 7 times.