Rolex has produced only two different models of moonphase wristwatches, references 8171 and 6062. Both models are automatic, however reference 8171 has a snap on back, while reference 6062, the Oyster version, has a water-resistant-type screw back.
The reference 8171 is considered very rare as it was produced in a small series between 1949 and 1952. It was made in stainless steel, 18K pink or yellow gold.
The present watch is the first example of this series with diamond-set numerals to appear in public.
An example of this model, reference 8171, is illustrated in The Best of Time - Rolex Wristwatches by James M. Dowling & Jeffrey P. Hess, p. 209.