I cant tell if there is any clear coating or not on this particular spring but, so far the color is just like it started out with no signs of oxidation. I am not familiar as you may be , with Beryllium Copper , with the time period it would take to start oxidizing or turning a different color , but with me having had this light very hot a number of times and also a number of hours running in all modes , would it not be showing some signs of oxidation by now if it were not coated?

EDIT: thinking about it I guess clear coating would also cut down on the current too……lol