About the only thing between the valve cover gasket and the part of the block with the stain is the cylinder head gasket. I can't think of any oil passages on that side of the head, but you might try a head retorque anyway. It can't hurt, and it might help.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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