A Boot Camp installation of Windows is able to be booted natively on your Mac's hardware - that's functionality that Apple ships as part of MacOS X 10.5.
It's Fusion that allows that same installation of Windows to be used as a virtual machine. This is the virtual machine that appears as "Boot Camp partition" in the Virtual Machine Library. Fusion recognizes a Boot Camp partition and sets up a virtual machine that directly uses the partition as its Windows disk instead of creating a virtual disk that sits within your Mac's file system.
So, yes, that Boot Camp installation can be "dual-booted", switching back and forth between a native boot (to run your games) and a virtual machine boot.
Side note - importing or converting a Boot Camp partition creates a new "regular" virtual machine (copying the Boot Camp parition's data) that can not be booted natively - it only runs under Fusion.