Within vCD, while in the 'MyCloud' tab...when I select the 'VMs' link in the left have navigation, this will display all my VMs. However, it does not display the External IP for each VM. Our vApps are NAT/routed, so they have Ext IPs. Is this something wrong with vCD or our configuration?
What version of VCD are you using? This is a known issue with VCD 5.1x systems.
upgrade to 5.1.3.
If you do, you can't upgrade specifically to 5.5.0.
Correct. vCloud 5.5.0 (released september 2013) doesn't have code to support a transition from 5.1.3 (January 2014).
The next release of the 5.5.x will support an upgrade from 5.1.3.
I just wanted you to be aware of that caveat.