Powder coating would require that you bake on the finish at 400 degrees, the mirrors would melt into a glob of plastic. As noted above, an excact color match to anything other than black would also be nearly imposible.
Your best bet would be to sand and properly prime the surface and paint with standard automotive enamel to match your truck. There are special primers and additives that will allow the paint to properly adhere to the plastic. I usually use a plastic primer and then add some flex agent as well, just like if I was painting a plastic bumper cover on a car.
Here's a link that better explains powder coating: