The head gasket and head bolts should both be replaced. Once you torque the head bolts down you've stretched them.
So, yes you should replace both. A lot of people reuse the bolts without a problem. If you pull the head you'd need to inspect the gasket and see if it looks perfect. It would be up to you if you'd want to reuse it or not.
If you feel you did a good job on the head gasket I'd leave it alone and go for the bracket.
Alternator Replacement - FWD/AWD 1998 and Prior - Volvospeed Forums
So, yes you should replace both. A lot of people reuse the bolts without a problem. If you pull the head you'd need to inspect the gasket and see if it looks perfect. It would be up to you if you'd want to reuse it or not.
If you feel you did a good job on the head gasket I'd leave it alone and go for the bracket.
Alternator Replacement - FWD/AWD 1998 and Prior - Volvospeed Forums