What does a speaker grille have to do with anything?
Surely you mean simply speaker, as the 'grille' would be the holes drilled into the phone where the sound waves travel out of.
iPhones have always had one speaker, by the way.
May I suggest digging into the bottom of the box the iPhone comes in... there is another package in there with these little things you can put into your ears and plug into the phone so that you can have better/louder/more private sound from your device.