Haven�t seen the speakers in question but many modern speakers ( pioneer, MDS etc. ) have the protection grille fastened with some "clay" stuff that won�t dry, easy to lift protectors off with a small screwdriver, with the speaker screws hidden behind
Might be worth a try before ripping the AC duct apart with the crowbar  ;-)
Good luck , happy new year, ride safe.....

Calle
-88 Vanagon
Mullhyttan,Sweden

>We've decided to finally replace the rear speakers and I have
> the front of the air conditioner grill off, but cannot see how you get the
> old speakers out. Any hints?