No, this not the truth. You got to install some KB's (which means, the patches) so that you can have the Server Core converted to GUI mode.
The below commands will work because, I have already install Windows Server 2012 SP0 with GUI mode initially and I'm just trying to convert it for security purpose. Because, only the server administrators will be known to some commands from which they would be able to manage the server in secured way.
- You will be prompted with CMD Prompt initially.
- Type powershell
- Ensure, Power Shell is running with Admin rights
- If not, use below CMDLET to run the Power Shell with Domain Admin
- Open CMD Prompt, "runas /user:microsoft\administrator powershell"
- Type administrator password
- In Power Shell type, Install-WindowsFeature Server-GUI-Mgmt-Infra, Server-GUI-Shell
- shutdown /r /t 0