My guess is that your side markers are probably bronze. You might be able to clean them with something, though I'm not sure what; maybe some kind of polish. I don't know if brass polish might work.
I believe it is the case that the pickups are cast in the housing, so you would have to replace the entire pickup. If it's within your budget to replace the pickup, you might want to correspond with Mica directly on this. If you send her pictures of what you have, there may be a chance that she will have an older one in stock that will match. Also, you may want to put a listing in our Wanted section. Some club members have replaced their AXY's with Fatboys; so there is a chance that someone may have an extra AXY that matches the one you are looking for.
