The freaking manual is useless and doesn't say anything about this and i think its odd. The other standoffs are all preinstalled. If I screw this down, the thread will be sticking upward. That is not how it's designed, is it?
That one may be for adapting something else and is included by mistake. Many radiator mounts need something like that. If it's body is same height as others, no harm in using it.