The Vicibox installer will download the latest SVN revision level of Vicidial during installation if internet access is available during installation of Vicibox. Some versions had an option to turn this feature off and just install what's on the disk, I don't know if that's still an option or not.
What this means is that if you install with the same CD today and a month from now, they will have two different versions of Vicidial.
The installer will, however, Match Version if you are installing a multi-server system. When you install the second (or more) server in a Vicidial Cluster, the system will check the revision level of the existing servers Database and Match that version in the new server so the code will match up and work properly. This is NOT a concern with a single server system, so it always just installs the latest revision.
Do you have a reason these two machines need to be running the same exact version of Vicidial? Or were you just curious as to how they could end up different?
UPGRADE instructions are in /usr/src/astguiclient/trunk
Please note that the SVN update itself merely updates the code available in the /usr/src folder, which is NOT in use. It's a repository of sorts. This "svn up" will not actually change your server at all. After upgrading the code there (with svn up), you still have to install that new code on your server and upgrade your database to match the new code. So read the upgrade documentation. It's not hard .... just technical. It's pretty quick though.