Assuming that the information given for them is true, and the bezel is aluminium (not some shiny plastic) then the answer is yes, they can be powder coated...assuming you can separate them from the body, and then get them back on! Best ask the powder coater to mask of the inner side of the bezel.
The chrome ring canít be removed without damaging it. I ended up having them painted as they donít match what I was looking for. Iím just about to replace the US multifunction lights and larger front indicators with the 40mm fronts and EU spec rear multifunction lights, so Iíll be getting them painted again.
Cant link to pic, but have a look at these threads