rear deck speaker cover on 1995 Mercedes-Benz SL320

I have bought two bose speaker covers for the rear deck how do I remove the old ones and replace them. there are four holes on the back of new covers but are they snap-in or screw holes? Do I have to get the whole rear deck carpeting off to do this? please show me how in detail.

Asked by for the 1995 Mercedes-Benz SL320