If you installed a series of licences on a workgroup, and want to see which licence is installed on a pc, you can use the following command to see last 5 chars of the key installed:

cscript "C:Program Files (x86)Microsoft OfficeOffice15OSPP.VBS" /dstatus

Before running this command, please make sure you have OSPP.vbs in C:Program Files (x86)Microsoft OfficeOffice15 folder.
If you have other Office versions installed you may need to change Office15 to the appropriate folder matching your office version.