Many believe that the stamp inside a Louis Vuitton bag is a serial number. Actually the embossed numbers and letters make up a production code known as a “Date Code”. The Date Code reveals where and when an item was produced. Date Codes are usually stamped or marked on the interior, although some bags like the Noé hides the code on the exterior leather trimmings.
N.B. It is important to remember that a Date Code does not by default guarantee an items authenticity. It should instead be seen as an instrument in establishing authenticity of a Louis Vuitton item.
Typically, Louis Vuitton will assign serial numbers to items that have been manufactured in their Special-Order workshop in Asniéres-Sur-Seine, France. Rather than being offered for sale in their boutiques, these items are often made to order by dedicated craftsmen in this small workshop.
The French Company
From 1970's through 1991 Louis Vuitton and The French Luggage Company in United Stated had a collaboration/licensed relationship. Goods therefrom have other markings and no date codes.
Louis Vuitton goods manufactured prior to 1980 have no date codes and can only be authenticated by meticulously inspecting the construction: brass pieces, hardware, lining, leather quality and condition, stitching etc.
Louis Vuitton starts marking their goods with three to four digit Date Codes, representing the month and year when the particular item was manufactured. The first two numbers represent the year and the last number(s) the month i.e. "836" would indicate that the item was manufactured in the sixth month (June) of 1983.
Mid to Late 1980s
Louis Vuitton ads two letters to the previous three to four digit date code. The letters represent the factory location. "VI8610" would thus indicate that the item was manufactured in France, October 1986. On some pieces the date code may be split up, showing the letters in one place and the numbers in an adjacent area. In the late 1980's, standards were set in place that ensured letters to always be placed before the numbers.
1990 to 2006
By 1990 some date codes were given a new format; having the year and month digits staggered. The first two letters represent the country, the first and third number represent the month, and the second and fourth number representing the year i.e. "SD0070" would indicate that the item was manufactured in USA in the 7th month (July) of 2000.
2007 and Later
In 2007 Louis Vuitton made further changes - date codes are now in week format. The first two letters represent the country, the first and third numbers represent the week of the year, and the second and fourth number representing the year i.e. "VI3058" would indicate that the item was manufactured in France in the 35th week (late August) of 2008.
Sometimes we come across bags that have contradicting date codes. This may be because the bag is not an authentic Louis Vuitton item, but it could also indicate that the item was repaired abroad.
Example: A Speedy was manufactured in France in 1998. After several years the interior had become very damaged from use, but the exterior still looked great. While being on vacation in the US, the owner decided to have the bag repaired by Louis Vuitton. When picking up the bag from repair at Louis Vuitton, the owner was surprised to see that the bag suddenly had a new date code. Explanation: Louis Vuitton never repeats date codes when repairing an item. Rather, they will add a new date code. The result is a bag that has “made in France” stamped on the exterior, but a date code that indicates the bag was manufactured in the US. By knowing that the bag was in fact repaired in the US it all makes perfect sense and we can verify the bags authenticity.