The Info Center data for your CPU is either simply hard-coded (to conform to the model used), or otherwise bogus. For instance, the Info Center tells me I have an INTEL Core i3-4130, with 2 cores, whereas 'more /proc/cpuinfo' correctly shows an i7 980X, with CPU 0 and CPU 1, each with 2 cores (exactly as I specified in the VM).
Pretty much the same here. I gave it 4 cores of a Xeon and it shows two cores of an i3