Yes it can leak from the rear seal on the intake manifold. I would replace the valve cover gasket first to see if it stops. I replaced all my intake gaskets 2 years ago to correct a lean code and hoped it would fix my oil leak problem as well, but it did not. BTW the intake gaskets and other hoses cost me $400 at the dealer because most guys say Felpro ones are junk. Good luck.
2000 F-150 XLT Ext Cab. 4.2L V-6 153K miles
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1970 F-250 Camper Special 390 Auto 293K miles