[CentOS] Sendmail, localloop, and iptables -- should I be more paranoid?

By default, sendmail only listens on the localloop:

DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl

But by default to allow sendmail to even work the iptables entry is:

-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 25 -j 
ACCEPT

Without this, sendmail can't even connect to localloop.  But should I 
handedit this line to something like:

-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp -d 127.0.0.1 
--dport 25 -j ACCEPT

And once you handedit iptables, you can't use the gnome firewall applet, 
I suspect...