We have heard from a few customers about this issue and have a solution for everyone hoping to address this problem. When you download Sharepoint Server 2016 from here, you will see that it states it is RTM (16.0.4351.1000). After the installation, the SPDocKit’s Farm Info report will likely show you the wrong build version number 16.0.4327.1000, which is a Release Candidate build number.
This is not an SPDocKit bug; this is a common case because not all updates affect the core farm code, so the number doesn’t get updated. Some other reports may use the wrong build number as well. Not only that, using the Powershell commands to detect the correct build version will give you the same incorrect information.
At this point, you will probably start asking yourself whether you have done something wrong. The answer is no—you haven’t. You have RTM, but due to the lack of schema updates, you receive the wrong build number.
However, there is a solution. You should install May CU (Language Independant or Language Dependant), which will allow you to get the correct build number. From here, SPDocKit will show you the correct data. You can also use “Is SharePoint up to Date” Best Practice report to check whether everything works properly.