[CentOS] vncviwer in listen mode poer number

I am working on the Centos wiki instructions for doing an install via vnc:
http://wiki.centos.org/TipsAndTricks/VncHeadlessInstall

CD is all burned and ready to go.  I then thought about the viewer 
settings particularly the port number and firewall rules.

When I connect vncviewer to a vncserver it uses port(s) 590n where n is 
the display number.  OK, is that what happens when a server connects 
back to a -listen viewer?

Seems not.  According to the man page, it seems the default is port 
5500, so I have to open up this port on the 'client' system and of 
course allow it through my internal firewall (or put the install system 
on the same subnet as the client and not the one with the repo server).

Do I this figured out right?