Hi musicmusic,
yes, "K" is indeed 2007, but it's not a "Z" but a "2" afterwards. See below info from the
Guild webpage:
"Dating Guild Instruments made in Tacoma, Washington after February 2005:
FMIC began building Guild guitars in Tacoma, Washington in early 2005. Tacoma made Guild guitars have a serial number consisting of two letters and six digits.
As an example, we’ll use a random number: TJ 037 016.
• The first letter “T”, identifies the guitar as being made at our manufacturing facility in Tacoma, Washington.
• The second letter identifies the year of manufacture and is based on a dating system introduced by the
Tacoma guitar manufacturing plant in 1998 that associated the letter “B” with that specific year. Successive
years are associated with the alphabet in sequence. Using this system, the letter “J” would stand for the
year 2006.
• The first three numbers of the serial number are derived from the “Julian” calendar which associates each
day of the year to a respective number from 1 to 365 in numerical sequence. These three numbers identify
the month and day of manufacture by their respective numerical order. In this case, the numbers 037
identify the instrument as being made on the 37th day of the year, which according to the Julian calendar, is
February the 6th.
• The final three digits of the serial number refer to the unit number built on that specific day. In this
example, 016 identifies this serial number as being from the 16th instrument built on that day.
• To recap this example: T (Built in Tacoma), J (Built in 2006), 037 (Built on February 6th), 016 (The 16th
instrument built on that day)"
Hope that helps,
Ralf