How can I tell if my replacement Rolex parts are authentic?

I recently had my Rolex fixed, but I don't know how to tell whether or not the parts are authentic. Do I get a certificate or something? Or can I tell by its structure?|||I have had mine repaired and I only received a receipt. There is no good way to tell. You can remove the case-back and compare the visible parts to that of a photograph on the NET. That is about all you can do. If the entire movement was replaced then it will be obvious because Rolex moments are all stainless with red writing. Most Chinese movements look like pot metal. Some appear to be plated in a gold like material. In either case they look nothing like a Rolex movement.|||Check with the repairer.