Intake Gasket advice

Oil in the ports would be from vacuum pulling it in from a crankcase ventilation system or getting past the guides. Some guys run oil catch cans to prevent oil in the intake.

If you have oil from reversion , that would be a serious ring sealing issue . If that is suspected best test would be a leakdown test and may be a good idea to run just to verify everything engine wise is ok.

An intake gasket leaking would cause a vacuum leak and pull air only and cause a lean misfire ,although the hemi has oil drainbacks between the intake ports on cylinders 1&3 and 6&8 those would be the cylinders effected and would have to be a really bad gasket to pull oil from there. .A sooty plug usually indicates a rich condition .