We have been tasked to disable reverse DNS lookups in postfix

We have added this option in the main.cf

disable_dns_lookups = yes

the option in the default.main.cf is

disable_dns_lookups = no

The issue is we are seeing no difference in the postifx logs as far as querying DNS. We still show some queries to DNS going out but don't know if this is reverse DNS lookups from postfix are just normal DNS queries from the host. Is there something specific we need to look for for Reverse DNS lookups?