How does one remove the two black plastic air vent grilles underneath the wiper blades on the 123 body?

I'm completely stripping my body to have body & paint work done while the engine's out. I'm almost done with everything else but these two grilles are driving me nuts. In the service manual section 82, the instructions for removing the wiper motor refer to job 83-140 to remove the grilles. So, I start flipping pages... and there's NO section 83! The book skips from 82 to 88. Great.

It looks like there are four little square caps on each grille that may be concealing screws. The square caps won't prise out, though. I jimmied with them until I heard something crack then decided to call it a day so I wouldn't pry too hard and break something in my frustration.

Any help?

"If it jams, force it. If it breaks, it needed replacing anyway."

- Nathan
'83 240D, 255k miles
'00 New Beetle TDI, 28k miles