If it goes down from the valve cover, then it's coming from higher up. But it doesn't have to be a faulty gasket. It can be the fit of the gasket to the cover. Or if tin covers, they have to have near perfectly flat flanges, because you cannot "torque" the 5 measly screws to overcome the bad flanges.
Speaking of the 5 screws, the seats for those screws are often torn out from years of being over-tightened. I like to use the Chevy-type load-spreaders on those lower "bolts".
Of it appears to be coming from the gasket, follow the gasket uphill towards the front until you find the trail from the valve cover coming down. I have never has a headgasket leak oil only. I mean I suppose it could happen but I really doubt it.
Many oil leaks that appear to originate at the valve covers are in reality coming from the PCV grommet, the breather grommet, or somebody just spilled oil on it while adding some. If alloy covers, many of those have had the baffles removed because they interfered with the rockers, and made ugly noises.
