I'm with Bret, re-use them if they look good....
If they are pitted by rust or damaged, I would replace them. If they look new and have been kept well oiled, I would use them. I never bought any new bolts or studs on my 466 with 14:1. Just 145 ft-lb in several steps in the correct sequence. I even re-used the Fel-Pro head gaskets over and over. On my 641", 16.5:1, Yes, I use studs, but I will re-use my head gaskets.