Bolt threads=grease, yes...or Loctite 242 which serves the same anti-corrosion duties, but also lightly glues the 2 parts together.

Everything else, flanges, hole bores, etc...Lube is unnecessary, but would not necessarily be harmful if you wanted to use it anyway. You may have to use a chainring bolt tool or very large flat bladed screwdriver to keep the nut from turning as you tighten the bolt head though. So, there is that to look out for.

I fasten aluminum bolts to 5nm with Loctite242 though 5-7nm is usually what is recommended with aluminum bolts. IIRC about 12-15-ish newton meters torque is recommended for steel chainring bolts. The Parktool website has a comprehensive table if you are interested.

IME it's best not to take a lubed bolt to the maximum recommended torque value because the lube makes it so that the running torque & all other sources of friction much less & you risk breaking the bolt/hole/threads/part from overtorquing. In chainring bolts, at least, the bolt head will tend to seperate from tension force before rotational force accumulates enough to reach the intended torque value.