Yes, you can reuse the head bolts. It is a good practice to replace them after three usages.
As stated above check the cylinder head bolts with a straight edge. If all of the threads do not touch the straight edge, then the bolt is stretched and must be replaced. Also check the threads for corrosion and/or damage, such as broken threads. Clean the bolts threads and lightly oil them for installation.
It is a good practice to chase the threads in the block with the correct tap, being extreemly careful not to cross any threads. Clean out the holes first. It is also a good practice to check the deck with a straight edge to make sure it is level within specification. The head should also be checked for any warpage. A machinest straight edge is best to use for the aforemented inspection of the deck and the heads surface, along with a set of flat feeler gauges. rangerj