I've heard stories of this, but I've also heard that if you are specific in telling them what you want then they will respect that.Rolex can be a minefield so many high quality clones kicking around and in essence Rolex retain ownership of the watch in the sense that when you give it to them for a service they decide which parts they will replace. You could own a beautiful 70s sub and it might come back to you with a new handset or in some rare cases even a new dial.
Their default is to make everything like new. They'll replace a spider dial (if they have a fresh one), unless you tell them not to.