Since most Rolex case backs have a date code stamped on the interior side, many collectors, dealers and auction houses use them to date Vintage Rolex watches. While this may be the most logical method, we should be aware that this assumption may not be correct in all circumstances.

 

1. A case back may have been swapped during service because of corrosion, cross-threading or other damage. An accidental exchange with another service watch has been known to happen as well. When changed out, the likelihood of getting the same date code is very low.
   
   
2. These codes were intended to to be a quality control number for the case backs themselves. The date codes were not intended to represent the date of manufacture for the watch on which they were used.
   
   
3. Rolex stamped case back reference numbers and date codes at the time of manufacture of the case back itself. After a batch of watches was assembled, the left over parts, including case backs, were used to manufacture additional watches at a later date. In these situations, the date code would be earlier than the production year of the watch in which they were used.
   
   The same Rolex parts philosophy can be seen on other Rolex references, such as the Daytona. It is normal and well accepted by collectors that early 6239 Daytonas have case backs that are stamped 6238, which were probably left over from the prior year's model. The same is true of the reference 6263, which ofttimes has the 6262 case back stamp.
   
   The following table shows a sampling of ten Submariner 5508 serial numbers and their respective case back stamps to illustrate this point.
   
   

Ref. 5508

Case No.  Date Code
361453    II. 1958
361631    II. 1958

399564    III. 1958
400034    III. 1958
400798    III. 1958

489937    III. 59
489967    III. 1958
490142    III. 59
490416    III. 1958

764292    II. 62

Another source of debate is the meaning of the Roman numerals stamped just prior to the year. Since most of these numbers appear to be I, II, III or IV, it is easy to jump to the conclusion that they signify the quarter of the year in which they were produced. However, it should be pointed out that there are examples of case backs with higher Roman numerals (right) than IV, which contradicts the idea these were quarters. A very similar coding system was used by Rolex on literature from brochures to guarantees. All the Roman numerals appears to be between I and XII, which suggests these numbers represent the month of production.

 

In conclusion, case back date codes can be a very useful indicator of the year in which a Vintage Rolex watch was produced. This is especially true when the year is confirmed by one of the charts or specimens from the same serial range. However, it should be noted that case back dates were not intended to represent the date of manufacture by Rolex per se.

Production and date codes on Rolex paperwork appears to use a similar date codes to case backs. A roman numeral, probably represents the month or batch number followed by the year of production.