So starting in mid-1976 the serial number was moved to a decal on the peghead.Even with the new system, Fender didn’t like to throw away a perfectly good serialized decal just because the year code would be incorrect.So, without any factories FMIC moved all guitar production during 1985 and early 1986 to Japan, while FMIC built a new factory in Corona, California.The Japanese-made Fenders do have some slight serial number differences (typically a “J” serial number prefix).So, they ordered neckplates that were supposed to have numbers above 100,000.But the stamper misread the order and thought that the number “1” was an “L” and so instead of plates starting with 100,000 they started with L00,000. But it took a while to manufacture and number the plates.
Generally speaking, a “S” prefix equals the 1970’s (In March 1985, CBS sold Fender to a group of private investors made up of the management of the corporation at the time.
Dating a Fender guitar with the serial number is a hit or miss propisition.
It helps narrow things down, but in most cases is an inexact science.
In 1957/1958 some serial numbers started with a minus sign (“-“), or had a “0” prefix before the number.
Also in 1959/1960 some serial numbers were at the bottom of the neck plate instead of the usual top.