Another curse with vintage Rolex comes from the abundance of spare parts, also called "service parts." These are authentic, in that they were approved by Rolex and often fitted in watches as replacement parts.However, as this operation happened after the initial production, their presence generally decreases the overall value of the watch.And still I would add the disclaimer "don’t try this at home" in the case of very high value Rolex where fakers have mastered counterfeits – the priciest Daytonas again come to mind.
Comparing with pictures of similar models that you can find in books or other trusted sources (emphasis on "trusted," as it is not unheard of for unscrupulous "experts" to simply make things up, especially when they are also dealers) is a safe starting point: it comes down to analyzing the shape of the Rolex logo, assessing whether it is should be applied or printed, and studying the font of the main lines on the dial.
This step should in most cases give you adequate information about the dial, and allow you to progress to examining other aspects of the watch.
Not really, as you next want to make sure that it is in good condition.
And here, words are a bit confusing, because a faded dial is not necessarily garbage: if the dial has faded to a uniform brown color, you are looking at a coveted "tropical" dial.
For instance, replacement hands filled with Super Luminova would noticeably contrast with an inactive tritium dial. One additional thing can be done about the dial: check whether it has some peculiar feature that could increase the overall value of the watch.