Just an update, the new NAV unit arrived within an hour of me driving to the dealership to check on it but I was able to get back out there late this afternoon and got it installed. It came with a version 5 disc and the service rep went ahead and gave me the new disc marked version 2. It has a GM part number on it but it doesn't match up with what the gmnavdisc website is showing but that's ok, I've got the NAV installed for my trip tomorrow and things are looking up.
Gotta start packing.
David