Check CentOS 6.5 has GUI desktop installed

I am working with a remote server with CentOS 6.5 and I have ssh access to it. Since I need to work with some graphic stuff (mostly testing webpages) I needed a rdp access to test and install a few things (e.g.: Firefox, Selenium). I installed xrdp and vnc (following this) and I am able to access this server with rdesktop but I only get a black screen.

Is it possible that there is no GUI Desktop installed? How can I check that?