Here is the meaning:
with automotive car paints as Dupont or Sikkens, ... ( it's what's available here in Belgium), you can mix in your clear coat some dropps of white pearl. It will give you a pearly look of your colour.
You can do it on this kind of "Light Gun Metal". In fact, it's what is done one the real beetle.
Be careful to not overload with "pearl" or your clear coat will become too "white" and you'll have a crappy effect.
I know 'cos my wife's VW Polo is painted this colour.
Deedlit