This is a curiosity but so far doesn't seem to matter operationally.
I have a Z90QQ7P unit that self-identifies (Client Information screen) and shows in WDM as being a D90Q7P. The label has the correct serial and MAC and reads Z90QQ7P 909805-01L. The unit is physically quite clearly the Z90QQ7P model.
Any idea why the internal identification is mismatched?
This might be because of the version of WDM. The current version is 5.7.2 and it's available for download at https://downloads.dell.com/wyse/ . If the product was released after WDM, more than likely the product tables are obsolete and the device will be misidentified.
Here are some helpful links: