There is not a movable camera under the R200. I wonder if what you are seeing is the removable magnetic plate. This covers up a magnet that can be used to attach the camera to a surface such as a monitor so that it can be mounted in place magnetically. If you are not going to mount the camera then the plate can just be left in place.
Last year, Intel released a 3D-printing project for downward-mounting the R200. It is meant for the caseless circuit board version of the R200 in Intel's "Vision Accessory Kit", but the principles may be adaptable for your project if you plan to use the regular cased USB R200.
You can find out more about the Vision Accessory Kit iat the link below:
Another good source of info about downward-mounting an R200 is the 'Tanked' project, where it was attached to a TV set above the area being observed.