If you're patching SharePoint Services 2.0 servers using SMS and the ITMU, check out this article:
The SMS 2003 Inventory Tool for Microsoft Updates cannot determine the status of a computer that is running Windows SharePoint Services 2.0 SP1
ITMU will fail to properly scan (and thus be unable to patch) servers that have Windows SharePoint Services 2.0 SP1 installed.
What's the fix? Install SharePoint Services 2.0 Service Pack 2!