Microsoft is not maintaining a separate build of Windows for DoD. They may have bespoke licensing agreements and support contracts, but military and DoD workstations run regular windows.
https://learn.microsoft.com/en-us/office365/servicedescripti...
>> Subscriptions in the GCC High and DoD environments include the core Exchange Online, SharePoint, and Skype for Business features. Given the increased certification and accreditation of the infrastructure, there are some feature differences between the general commercial Office 365 offerings and those available in GCC High and DoD.
Whether or not "windows professional with group policies" constitutes "their own version of windows" as per bongodongobob is left as an exercise to the reader.
Okay, it's the same operating system, but DoD managed devices have a different set of features and capabilities that are allowed to run on that device so I would contend that counts as a different "version", if the disagreement is semantic so be it