Instructions
Remove the watch strap on both ends. Look between the lugs at the 12 o̵7;clock position for a case reference number.
Look between the lugs at the 6 o̵7;clock position for a serial number. Write both numbers down for reference.
Identify the serial number for the date of the watch. A 1931 Rolex will have a serial number between 28000 and 29000.
The watch should say ̶0;Rolex Auto Rotor̶1; in an arc along the top of the watch face. Turn the watch over and examine the back of it. It should say ̶0;Swiss Made̶1; and ̶0;Patented̶1; in the center of the case back.
View images of an authentic 1931 Rolex Oyster Perpetual watch online at websites such as Science Museum.org.uk or in reference books of antique Rolex watches, which can be borrowed from your local library or purchased at local bookstores or online. You may need the serial number or reference number to correctly identify the watch. One such book is ̶0;Rolex Wristwatches: An Unauthorized History (Schiffer Book for Collectors)̶1; by James M. Dowling and Jeffrey P. Hess.