Thanks for posting this guide. I had a bad display connection that caused my Mac display to go off (black) every now and then. Remote desktop showed Mac was fully functional, though. Removed the glass, removed the LCD as per this guide, cleaned all display connectors with WD40, mounted everything back and… voilà !
Marcos, there's no "front housing". The whole thing is composed of two parts: the speaker and the polycarbonate housing. The speaker is attached to the housing via 3 screws (step 1 in this guide)
But maybe you're talking about a grille some of these speakers have, over the driver, that can be easily removed - just pull it out.