If you look within your WsusContent directory, you'll see all of the updates divided into folders. These folders represent the last two chars of the update GUIDs. Unfortunately, this is how WSUS catalogs all of the update files. So, assuming you know which update corresponds to its particular GUID, you can manually run the updates on the target machines.
Of course, not having a WSUS install precludes you having the ability to scan for needed updates, and you lose the associated update automation. Since you're halfway there, you should finish the job and create a WSUS server on the disconnected side and import your updates and metabase there.