Does anyone know if the "pebble grain" on top of the buckle is actually in the top black coating material or is it in the metal portion of the buckle? I have a couple of buckles that have small rust bubbles in them and I'm trying to determine if I can take a wire wheel to them and strip them down to bare metal and the pebble grain still be there or if by removing the top black material the pebble grain will be removed?