[mocwon]

You should be okay reusing the head bolts given the short amount of time they have been on assuming they were new to start with. When building up an engine I never reuse head bolts, rod bolts or main bolts. Bolts fatigue over time and not knowing how many times a bolt has been re-used or the punishment an engine has been through can be risky. New fasteners are cheap insurance. ARP provides a torque chart with many of their fasteners so you can keep track of how many times they have been torqued, what they were torqued to and if you really want to go all out how much stretch each fastener sees.