Those are the OEM lower adjuster fittings.
Due to body/panel variations, these are designed to provide a tight fit to the lower body mounting tabs.
Here's the process :
When re-installing the unit, get it in place with the eyebrow light inserted, screw these adjusters in just so they are started properly,
secure the upper two bolts, then screw the adjusters in until they just contact the body mounting tab.
Now insert and tighten the lower 2 bolts.