Since the 1980s, Louis Vuitton has used date codes and serial numbers to track its products. Little is published about how these combinations of numbers and letters are arranged, but there is method to the code madness. With a little perseverance, cracking the code becomes second nature.
Locate any number or letter codes embossed on the inside of the handbag.
Look to see if the code is labeled. Authentic Louis Vuitton handbags have date codes or serial numbers. Louis Vuitton has never used anything called a model number. This holds true even for vintage pieces. If you see the label "model number," the bag is a fake.
Determine if the bag is an item from the "French Company for Louis Vuitton." The French Luggage Company did not use date codes or serial numbers, so these pieces have neither.
Break the code down into its components. The purses have a 3- or 4-digit code. The first 2 digits are the year and the last 1 or 2 indicate the manufacturing date. The first 2 digits are always higher than 80. The last 1 or 2 digits are always between 1 and 31.
Follow the code guideline that refers to the year the bag was produced. In 1990, the coding system changed to 2 letters followed by 4 numbers. The letters indicate the factory of origin. The 4 numbers are the manufacturing date, but now the date is staggered. The first and third numbers are the year, while the second and fourth numbers are the date. When examining the date, put the numbers into the right order and verify that they represent a plausible date. Code format changed again in January of 2007. 2 letters still represent the factory of origin. The 4 numbers that follow the letters are the week and year the bag was made.
Louis Vuitton started using date codes and serial numbers in 1980, so no piece manufactured before then has either codes or numbers. If the bag you're looking at is supposed to date before 1980 and it has a number or code located anywhere on the bag, it's a fake.
Knock-offs look more authentic every day. If a bag's a date code or serial number conforms to the above pattern, it doesn't guarantee that the item is genuine. Don't let changes in code format confuse you. Purses made in the late 1980s have codes comprised of 3 or 4 digits followed by 2 letters. The first 3 of 4 numbers are the manufacturing date-year first followed by day. The letters indicate the specific factory of manufacture.