This is rather common misconception. Norton Ghost and Symantec Ghost (or Ghost Solution Suite) are two different products, based on different technologies, which confusingly share a similar name. This forum is focused on GSS, which is the enterprise product line.
Still I went ahead and did a bit of research for you. A forums site for Norton Ghost would be here -
http://community.norton.com/norton/board?board.id=other - together with the other Norton consumer line up.
For your specific question, I am not aware whether Norton Ghost team makes updates available outside of LiveUpdate, but my guess is no, since LU is the default update distribution mechanism in Symantec. You might want to look at this article:
http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2000100610540448?Open&docid=2003071516005313&nsf=sharedtech.nsf&view=docid
It describes how to set-up internal LiveUpdate server (you could just use UNC path), and then prime your internal LiveUpdate cache from one machine that would have connection to Internet. Then the machines in your lab can be modified to request their LU from this internal share (or server).
Hope this helps.