[kieselguhr]

From personal experience, Rolex Service Center refused to service a Submariner that I had purchased locally as it contained numerous aftermarket parts including dial, and movement components. The in house watchmaker at my AD agreed to help me out and after restoring the watch with service parts, I sold it at a loss.

Parts are likely easily identified by technicians who work on these movements every day. Parts that are questionable are likely flagged by the tech and verified by the watchmaker.