Luxury watches come with a variety of numbers associated with them on the paperwork, case back, chronometer certificate etc., but which numbers are really significant? We are often afraid of giving the serial number away because of the growing replica market that has been taking these numbers and using them in a disingenuous way. However, without knowing it, many people mistake the watch serial number as the watch model number. For example, it is a common mistake on Cartier watches to blur out the case number instead of the watch serial number on online eBay listings.
So how do you find a watch model number? It depends on the brand. While some watches will not have a watch model number on the physical watch case, surprisingly, many of them do. The paperwork is always the first option for locating a watch model number, but unfortunately many times the papers are misplaced or lost. Here are some top luxury watch brands and some tips on how to find your watch model number. But first, some common mistakes: • Movement as watch model number- sometimes the movement number is marked on the watch. 
The watch model number is usually referred to as the “style number” on Rolex paperwork, if there is paperwork on the watch. Luckily, there are some dial markers and case features that can usually give away a Rolex model number, but some models, such as the 18k Ladies Date-just line, can be difficult to discern. One of the many special aspects of a Rolex watch is the unique, five to eight-digit serial number on each timepiece. Performing a Rolex serial number lookup.
A good example is the Montblanc brand. A lot of their watches have exhibition case backs where one can see the rotor. The rotor is marked with the caliber. Many watches will contain that same movement and so that caliber number might lead one in circles if mistaken as the model number.
• Watch Serial Number- as mentioned before, we often assume the model is a serial number which is a unique, one-of-a-kind number • Chronometer Certificate- while definitely valuable to the watch, the number on the certificate will not help you search for or identify a particular watch • TIP: If “model number” isn’t stated verbatim look for the term reference number or style number on the paper work Jaeger Le-Coultre can be a little complicated, but we expect nothing less from such an intricate brand. There are sometimes three models that can identify one Jaeger LeCoultre watch. Some watches are more commonly identified by just one of these numbers, while others are referred to by all three. A Reverso, for example, is commonly known by the number on the back of the case. This model is usually in the form XXX.X.XX or a similar format.
Jaeger Le-Coultre watches also have what is known as a “Q” model number. For instance, the Reverso Gran Sport has a “Q” model number Q2948102 and a case back number 295.8.51, both of which are searchable. The “Q” number will be on the paperwork and tag and the other on the case back. Occasionally, a longer watch model number will be listed on the paperwork as well as in a similar format to the case back number. This often does not search for the watch but is a genuine watch model number.
Your best bet with JLC is the “Q” number or case back number. Cartier, much like Jaeger LeCoultre watches, typically have a number on the case back and a unique identifier on the paperwork that will designate the model.
The case back number (typically 4 digits) dictates what the case will look like. The materials can vary even with the same case back number, but the size and dimensions will be the same. Many people mistake the longer number on the case back, which is the watch serial number, for the watch model number. The 4 digit number is very important in identifying the watch. The other model number typically starts with a “W” and is found on the paperwork only. This number is the specific model number that will correspond to only exact matches of the watch.