MacOS Serial Number
Apple devices manufactured after 2010 generally have 12-character alphanumeric serial numbers, with the first three digits representing the manufacturing location, the following two indicating the year and week of manufacture, the next three digits providing a unique identifier, and the last four digits representing the model number.
Serial number example: C02L13ECF8J2
The fifth character represent the week in which the device was manufactured. There are 28 possible characters in this spot: the digits 1-9 are used to represent the first through ninth weeks, and the characters C through Y, excluding the vowels A, E, I, O, and U, and the letter S, represent the tenth through twenty-seventh weeks. For devices manufactured in the second half of the year, add 26 to the number represented by the fifth character of the serial number. For example, a product with a serial number whose fourth and fifth digits are “JH” was manufactured in the 40th week of 2012.
The next three digits are an identifier code which serves to differentiate each Apple device of the same model which is manufactured in the same location and during the same week of the same year, ensuring that each device has a different serial number.
The last four digits of the serial number represent the product’s model.