Kinda depends on which gaskets you have? Are they the old NOS original asbestos hard gaskets? If so I would put OMC gasket sealing compound (NAPA Aviation sealant) on them. It’s non hardening & will allow removal for the near future. Grease could be used on them to soften them & make them reusable?
If you are using the newest style gasket that have the shiny/sticky substance on them then no sealant is required. These gaskets are a lot thinner and retain torque much better without sealant or grease. They will stick after heat up! I would not grease them & sealer is not needed.

Dan in TN