Well, if you find a beautifully Rolex which looks like new… whereas there is another one may have lines of scratches and traces of usage… everyone will pick up the new one first, but I do hesitate… all we have to check the case has been polished after leaving Rolex Factory.
As if they have been polished many times… though it looks like NEW, but the Rolex oyster curvature and profile may be lost. And the watch looks a bit “Thin”. When you pick up a new Rolex, is “Fat” meaning that they have muscle on all corners, slugs, and it look wider.
The how to tell a Rolex case has been polished? I usually look at the for surfaces of the slugs. If they are original un-polished, it has a rectangle shape with shape corner edges. if the watch has been polished , especially by non-professional operators, they look filmsy and the rectangle will be gone.. If a professional operator could polish the case removing all scratches and lines and at the same time restoring the rectangle, yes, it can, but the overall watch length will be shortened.. Experienced Watch collector can easily tell by comparing two Rolex side by side to tell the length of it…but most of the cases, the about check can tell how much the case has been polished and is good to serve our purposes… and most of the case, the Shop keeper will be hesitate for a customer to do such a stringent body-checks!
A polished case will lose it value. But not too much if they have been polished lightly. But if we are buying that Rolex for Collection, of course the first choice if going to the un-polished one…
In another cases that non Rolex AD Rolex may be Restored… so you do have to check also see if that has been undergone some polishing works to restore the original luster with trade off of the "Fatness" of the Oyster.