We can check, but I believe it is a plasma, DLC, or similar type coating, rather than plating.
If it happens to be a plasma based sputtering procedure let me know, I think these easily have the metal switched...I may want to plate a gun with niobium. I can supply the niobium.
Then I can make an entire gun this shade of blue http://theodoregray.com/PeriodicTable/Samples/041.26/index.s12.html