'68 289 - Head bolts - RTV? Oil?

I'm pretty sure(100 %) that the head bolts do not go into a water jacket.
If they are the old bolts being re-used, a light coat of oil won't hurt. If they are an aftermarket/ ARP then I believe they go in dry.
 
If they are an aftermarket/ ARP then I believe they go in dry.

Yikes! Any head bolt, ARP I know for sure, should have at least oil on it or better yet a moly lube. Just remember to adjust torque spec accordingly. A dry bolt will have less clamping force than the same bolt at the same torque with moly lube because of the friction between the threads. If you use moly lube use the low end of the torque spec.