i wouldn't worry about that, most l series cars will do that, I have found that the Gasket on the Rocker cover can split at the back of the motor, Against the Firewall, i had that happen to me on a trip and it sprayed a fine film of oil over the firewall,
its an easy job to do, pull the cover off, clean both surfaces, and put some Blue gasket glue in the place of the original gasket, refit, easy as