'reject_non_fqdn_helo_hostname' and 'reject_invalid_helo_hostname' neccessary?!

[Nikolas Kallis]

Is using 'reject_non_fqdn_helo_hostname' and 
'reject_invalid_helo_hostname' even neccessary when using 
'reject_unknown_helo_hostname'?

The way I see it is if there is no FQDN and the host name is invalid, 
then 'reject_unknown_helo_hostname' won't be able to verify the DNS A 
and MX record anyway, and would reject the mail... Right?