Circa dating system
ABOVE: Around 2005, Rolex started engraving the Case's Serial Number into the inside edge of the case (at the 6 o'clock position, under the crystal and below the bezel), also known as the rehaut, as shown in these images, which were taken at BASELWORLD 2005, in Switzerland in early April.
BELOW: A close-up view of the same watch, you can clearly see the Serial Number "F982176", engraved into the case at the 6 o'clock position, with "ROLEX" engraved repetitiously around the dial in a circular fashion.
The simple rule is that adding 1927 to the number give the year of production.
This second use of the ‘standard’ mark is believed to have continued until about 1936.
Thus spelling out the word "ROLEX" with the "O" being omitted, to help avert any possible confusion with the number "0".
This sequence continued through November 1991, when a new numbering system was introduced utilizing the letters N, C and S, which took them through 1993.
While it was originally believed that this resequence started over at 100,000, or even 20,000, but evidence suggests that it actually restarted at 10,000 or possibly lower.
Virtually all Doulton tableware has a black printed Doulton ‘mark’ or ‘backstamp’ applied to the underside of the piece.
The mark was varied from time to time and the table below includes the major marks that appear on tableware manufactured at the Doulton (Burslem) factory (Series Ware and the Lambeth Stonewares often have special marks).
The new mark and use of the name ‘Royal Doulton’ as opposed to ‘Doulton’ signify the grant of a Royal Warrant to Henry Doulton by King Edward VII in 1901.
From 1922 or 1923 until the end ( presumably) of 1927 tableware appears bearing a mark that lacks the traditional crown.