Assuming your are really doing this for study and not for any hacking / or trying to know something which is restricted to you in your environment.
If you are asking this question you donot have RDP/SSH access to the vcenter server.
You can ping the vcenter host and find the mac address using the arp table on your local machine. From the mac address you can find the manufacturer of the NIC. (Paste mac in google, it will find the manufacturer for you). If manufacturer is VMWARE then its a virtual machine. If it is something like intel or any hardware manufacture its a physical server.
I am posting this answer after 6m.. you may not need this anymore. But the question looked interesting.