How are you wanting to create the labels? Printing or engraving?
I would get some 1/16" black (or any color) on white engraving plastic from Gravograph or Rowmark. You engrave through the top layer to reveal the white core. You could either make a label that goes above the switch and attach with double sided tape or a label with the mounting hole in it and have the switch mount through it and your box. These are commonly refered to as lamicoids/lamacoids in industry.