Will permissions provided through Cloud IAM be reflected in the ACL s or vice-versa

Question

If both Cloud IAM and ACL's work in tandem, will the permissions provided using cloud IAM  be reflected on ACL's and vice-versa? so that there is no need of explicitly configuring the other?

Answer 1

Permissions can be granted either by ACLs or Cloud IAM policies. 

In general, permissions granted by Cloud IAM policies do not appear in ACLs, and permissions granted by ACLs do not appear in Cloud IAM policies. 

The only exception is for ACLs applied directly on a bucket and certain bucket-level Cloud IAM policies, as described in Cloud IAM relation to ACLs.