They're not pre-tapped holes. Instead, they are three studs that will stick out from a plate that is accessable from the inside of the car through the cubby bins. When you remove the nuts, you could actually take those plates out if you wanted to, leaving three holes. (I'm not sure why they are even there!)

If you're good at fabricating things I'm sure you could come up with a way to mount a bike rack to them, although the driver's side may interfere with the exhaust.

When you're down there take a look and it should make more sense...

Hope this helps! :)

BB.