Guide to locating Model Reference and Serial Numbers

A quick How-To guide for locating these numbers on your Polarouters and Polerouters.

Guide to locating Model Reference and Serial Numbers

Universal Geneve were very systematic in their combinations of cases and dial colours, logos, hour markers, hand combinations and luminous material, and they reflected these combinations with specific model identifiers – what we call the Model Reference Numbers

The Model Reference Number defines what the watch should look like, and in many cases so does the Serial Number. There were occasionally some small production changes throughout a reference number production, and these changes occur at specific Serial Numbers. For example, the change from early serial “Microtor” dials, to later serial “Automatic Microtor” dials for 20360, 20363, 204503, 204504 and the change from early serial “Automatic Microtor” to later serial “Automatic” dials for 204610, 204602, and 20365, amongst others. 

All Polarouter and Polerouter models have, and are defined by their specific Model Reference Numbers, and their Serial Numbers (discounting some locally-cased US-market watches). So, it can be very reassuring for a collector to find everything matching, just as it should.

Locating these numbers can be difficult due to wear and tear or polishing over the last 65 years, and the location of these numbers on the case also varied throughout the production period. There are 3 locations that a Model Reference Number and Serial Number can be found on a Polerouter:

1. Between the Case Lugs

This location is so far only seen on the early steel and gold-capped microtor models, i.e. 20357, 20360, 204503, 204504, and 20363. Some examples of these references were found to have the numbers stamped on both on the outside of the caseback, as well as between the lugs – though so far, they only appear like this very late in the serial ranges.

The specific location is usually between the top lugs, thought there are some claims that they have occasionally been seen on lower lugs (though I am yet to see any physical proof of this). The Serial Number is always located directly below the Model Reference Number.

2. Outside of Caseback

This is the most common location for the Model Reference Number and Serial Number on a Polerouter. This location is used on, for example, all Polarouter and Polerouters powered by the 138ss Caliber, and all Polerouter and Polerouter Dates with applied U logos onwards (e.g. 20366, 20368, 204605, 204607, 204610, 204612, amongst others). Also seen on all Polerouter Jet, Polerouter NS, Polerouter Geneve, Polerouter Super, Polerouter Sub, Polerouter III, and all 18K Polarouter and Polerouter models.

The specific location is usually around the outer edge of the outside of the caseback, but it also varied in relation to the Polerouter logo in the centre (for those models that had it). Again, the Serial Number is located directly below the Model Reference Number for most models – though there were a few exceptions, such as the 20369 Polerouter Sub, which had the Model Reference Number on the opposite side of the caseback, to the Serial Number.

3. Inside Caseback

This location is often seen on some of the latest production references, including the 869119 and 569119 Polerouter Dates, as well as the late Polerouter Sub models 869120, 869121, 869123, and 869124. The sub-reference is usually missing from the inside of the caseback, but the full Model Reference Number wit sub-reference was present on the outside of the caseback.  In the case of the late model Polerouter Subs, 869120 was usually stamped on the inside (sometimes with an extra 1, 2 or 3 above it), which did not match to the Model Reference Numbers stamped on the outside of the caseback (e.g. 869120 inside, and 869123/02 outside). Another curious, yet consistent detail.

Tips and Tricks

If in doubt about where to find your and Model Reference Number and Serial Number, first try to identify your model visually from the Reference Gallery, then cross-check this with the serial locations column in the Reference Tables.  Often the casebacks are worn over time, and numbers between the lugs can be worn away by straps, bracelets, or polishing. The numbers were usually quite shallow into the metal, so are usually difficult to see without the assistance of a loupe, or magnifying glass. Try viewing the areas it should be located in, from different angles in both natural and in fluorescent light, under a loupe. Some have also reported success by using tracing paper over the caseback (though I am yet to try this method myself).

And finally, of course, if you find a new Reference Number (or Serial Number) on your Polerouter that we have not described yet, please send us a photo and description using the Contact Form.

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