Hood latch adjustment bolt with free-spinning head, WTF?

Trying to pull my old, broken hood latch off to fix or replace it, and found that the bottom of the three bolts has a round head that just spins and spins. Maybe it's designed to be turned by hand for the adjustment? I don't know, but I can't figure out how to get it off?!?! See pics. Any ideas?

1st image is looking straight down between the grill and the radiator. That round disc inside the red circle is the culprit. It just turns and turns.
2nd image is the same bold head or whatever it is, as seen through the front grill.
3rd image is from the FSM, showing a normal bolt below the latch (which is not the case)

 

It’s just a plastic cap. The bolts behind it.

 

Thats what I thought too, but spin it to the left and it loosens to adjust the height of the latch. And I can't spin it off or even pry it off with a flat head.

 

looks like the cap actually sits inside the bolt. I never tried to mess with it so I'm just going by the diagram.

 

theres a bolt there. remove cap. get better view by removing grille