If you get the later (late '88) with the UPTURNED lip
and don't use ANY GASKET AT ALL, you can usually keep them from leaking.
CLEAN the valve cover gasket rail CAREFULLY with solvent and a scraper.
Ditto for the valve cover itself.
CAREFULLY tap down any "dimples" around the bolt holes that are a result
of previous overtightening.
Then lay a bead of "ultra grey" silicone onto the head and carefully reinstall the cover.
To do this "right" will require you to remove both engine lift ears (if not previously removed) and unbolt BOTH the Alternator and A/C compressor (if equipped) to
give you sufficient working room.
If you just want "gaskets" then get good ones that include an anti-crush spacer moulded into the gasket.
AD