I don't know what it's called...but is it possible to take out that rubber peice that covers the switch on a mag and 'switch' it with another mag? I have a nice mag with a ripped switch, and a beat up mag with a nice switch...
I've just done this with my 2 mags and it's really easy. Just pry the rubber sleeve off with a sharp knife and slip it in the other one! simple as that.