There are two options here.  The first and easiest is to have ZENworks Service Desk use the host name for hardware or the bundle name for bundles as the item number.  To do that see https://www.novell.com/documentation/zenworks-service-desk-82/service_desk_with_zenworks/data/importing_items_using_zenamie.html#b1elt5v7 - under step 6 there are the screen shots that show the drop down for "Item Number" that could be system generated (the sequential item numbers no technician or customer likes), or host name for hardware, bundle name for bundles.

The other option is to keep the item numbers as is and on the Item Types choose an identifier such as Network Name.  This would make the items show in lists as "100232 - pc001" for a machine named pc001 with the item number 100232.