Any way to detect dual processors without opening up the server?

Hi

Just a quick question really, I am trying to find out which of the servers have actual dual processors and which are just dual core.

I got told the WMI win32_computersystem attribute of ‘NumberofProcessors’ would be accurate but some servers are displaying as 4 processors when I know for a fact they only support 2 processors albeit dual core.

Anyone got a surefire method without having to take apart the hardware?

Thanks