1965 skylark exhaust manifold bolt question

Were flanged bolts used on the exhaust manifolds of a 1965 skylark with 300?

 

No, typical hex head bolt.
(and the steel "French" locks)

 

Thanks would you happen to know the length of the bolts and what grade they are?

 

I believe 3/8-16 X 1 Hex Head (stainless grade 5), and use anti-seize and reduce torque by 20% due to reduced friction.