Serial number verification

7-digit serials are the most common:
The first digit = the year it was made

For example: a serial number beginning with 2 indicates a guitar made in 1982
It is possible that the second and third digits give the month.

Addendum November 2014:
6-digit serial numbers:
Several Westone forum members have recently presented guitars with 6 digit numbers. Although not as common they do exist.
Looking at dating information compiled by our friends at the Matsumoku Forum  we note that 6 digits was in use until mid to late 1981.

We presume that the interpretation for those instruments is the same for early Westones, until the 7 digit scheme was applied:

The first digit (0 or 1) = the year
The next 2 digits = the month

5-digit serials appear on some models:
The first two digits = the year
The last two = the month

It is important to note that these are not really serial numbers, just production dates, and are not unique…84009 is extremely common!

8 digit serial numbers:
These appear from late 1987, in the format NN NN NNNN (eg 87 10 0001).
We think that:

the first two digits = the year
the second two = the month

Any guitar with this sort of number was probably made in Korea.
Later models (1987 onwards) have no obvious serial number and may have originally been on a sticker on the guitar.
These are also Korean  made.

Letters in the serial number
Many early 80’s models are also seen with a letter prefixing the number.
These represent the production month and are interpreted as:

A = Jan D = Apr G = July J = Oct
B = Feb E = May H = Aug K = Nov
C = Mar F = June I = Sept L = Dec
So, a serial number like D810040 would indicate that the guitar was manufactured in April 1981.