Most Electromatic hollowbodies carry a KS designation, although KP was fairly common prior to about 2007.CY is usually seen on Electromatic solidbodies such as the Corvette/CVT.Unfortunately, correct information can be very difficult to come by.
Lower numbers will always appear on earlier guitars, higher numbers on later guitars.
Remember that 20 guitars will, of course, not begin with a 9.
After World War II, some guitars had a serial number embossed on the head, but reliable numbers didn't really appear until the advent of the first labels, around 1949.
Early labelled Gretsches will usually have a printed serial number and a handwritten model number.
Also, on guitars built in October, November or December, the third AND fourth digits denote the month.
Serial numbers on Korean made guitars in this era were printed on a sticker affixed to the back of the headstock.
As of July 2011, the current thinking is that the first digit probably denotes the year, while the following numbers remain a mystery.
This only pertains the pre-Fender Korean-made guitars.
However, some have "Gretsch" printed as the familiar logo.
Beginning in about 1957 a new label was introduced, which lasted until about 1965. Co." was printed in black on an orange shape that vaguely resembles a musical note. On the white part, the serial number is printed, and the model number should be handwritten.
Gretsch used several different serial number schemes through the years.