1.6 8 valve Head Gasket

Removed cam box last night(without manual) and discovered same bolts secure head. This has probably disturbed the head. Do i need to change head gasket and skim the head. Are new bolts required? The head gasket had not blown, problem was cracked box at top pulley caused by bush mechanic and an axe. What is torque setting for bolts and sequence for tightening.
Come on guys give me a response
Car is 97 Corsa import