The present lot has the cancelled reference number 5018 as well as the number 5016 in the case back. So-called ?Bombay? by collectors due to the shape of their lugs references 5016 and 5018 differ in the type of seconds indication 5016 having subsidiary seconds and 5018 centre seconds. The caliber 620 was created in 1936 and was in regular production between 1940 and 1951. This watch is illustrated in ?Rolex Collecting Wristwatches? by Osvaldo Patrizzi 2001 Edition p. 170.