It is possible to use Device Licence Unit (DLU) with Call manager express ?
These are two distinct models as far as Licensing goes so these DLU's would not be an asset for a CME Install:)
Prerequisites for Configuring Cisco Unified CME
Base Cisco Unified CME feature license and phone user licenses that entitle you to use Cisco Unified CME are purchased.
From this newer CME doc;
Hope this helps!