Mof Edit for HP SKU Number
I was looking into this, and realized I've already done this! I just didn't know it. http://myitforum.com/cs2/blogs/skissinger/archive/2009/03/13/hp-quot-enter-ownership-tag-quot-mof-edit.aspx
In that case, the person was specifically looking for a "Enter Ownership Tag", which is in that namespace as well. In that exact same WMI location on HP workstations are other interesting bits of information (which have the HP Client Management Interface installed, if you image your computers, you may not have CMI installed).
Some of the other interesting pieces of info you can report on once you have that mof edit + HP's CMI installed are these:
Product Name (HP Compaq dc7900 Small Form Factor) fyi, same info in win32_computersystemproduct
SKU Number (NJ804UP#ABA)
Chassis Serial Number (fyi, same info in multiple other places)
Asset Tracking Number (usually the same as serial number, but perhaps your company has a special process)
Family Name
Enter Ownership Tag
I've heard multiple times of people looking for "where's the SKU number" for the HP product. Because in win32_computersystemproduct it just has the Product Name, and they need the SKU# instead. So the edit in the mentioned blog entry will get you SKU#, as well as some other information.