<VV> Is there a trick late to LM Monza rear grille install / remove?

[Charlie]

Hi again ~

Now that the 140 engine is in the 1967 Monza, I did a little cosmetic work, such as trying to install the rear grille...

The Monza does not have a removable panel in it (like the Corsa panel does) to get at the screws.

So, is there a trick to this, or is it just a matter of poking around until I get lucky? 

I get lucky with one of them, but I was not as lucky for the next hour before I gave up ~ is that why so many LMs only have a few screws holding the rear grille?

If there is there a trick to this, what is it?

Thanks!
Charlie