Quick postgrey install question on FC7

[SSS]

I'm trying to get grey listing running on my mail server.
I've had a read of the wiki and think I can follow the steps ok.

Server is running Fedora 7 with ZCS 5 on it.

I'm just a bit nervous about the first step, installing postgrey as the wiki only shows steps for Ubuntu, which is fine as it looks like the only Ubuntu specific code looks to be the apt-get command which I can alter to yum install for my system.

When I run "yum install postgrey" it finds some extra dependencies that need downloading/installing, including postfix, which is what Zimbra uses if I'm not mistaken.

Dependencies Resolved

=============================================================================
 Package                 Arch       Version          Repository        Size
=============================================================================
Installing:
 postgrey                noarch     1.27-4.fc7       fedora             40 k
Installing for dependencies:
 perl-BerkeleyDB         i386       0.31-3.fc7       fedora            146 k
 perl-IO-Multiplex       noarch     1.08-5.fc6       fedora             20 k
 perl-Net-Server         noarch     0.95-1.fc7       fedora            150 k
 postfix                 i386       2:2.4.5-2.fc7    updates           3.6 M

Transaction Summary
=============================================================================
Install      5 Package(s)
Update       0 Package(s)
Remove       0 Package(s)

Total download size: 4.0 M
Is this ok [y/N]:

Am I ok to continue the install like that? I'm not sure if installing/updating postfix with yum will effect Zimbra at all.

Still a bit of a novice when it comes to installing stuff on Linux. Yum is my friend... usually

[SSS]

So do I need to worry about yum installing/reinstalling postfix?