If you are unsure if the digit denoting the year is in which decade (1957, 1967, etc.) then try to determine this by the amplifier it is in.Tweed amps were made from the very early 1950’s through approximately 1960, blonde and brown amps were introduced around 1961 through 1965, blackface amps with black tolex started around 1964 through 1967 and silverface amps took over in 1968.Subtract one from the other and I'll have a rough-cut figure for how many were made. PRII owners were kind enough to start sending their serial numbers in.I was puzzled to see how some of them were separated by over 100,000.Fender guitar amps have been a constant in rock music, featuring legendary clean tones, lush spring reverbs and, in the case of the newest solid-state models, some of the best modeling and built-in digital effects available today. After all, with so many different models, it may get a bit complicated...so let's go back a bit to have a look at the history of Fender amps, at some famous users, and find out which are the best Fender amps you can find today!
So if the number on your potentiometer is 304728 it is decoded like this: 304 is the Stackpole manufacturer’s number, 7 means 1967 and 28 is the 28 week of 1967.
All green board and all cream board Blues Juniors are identical electronically, despite what the salesman told you. Below is a table of revision dates and the changes made on those dates. Fender adopted a two-letter dating code in 1990, and the code can be found on the Quality Assurance label, inside the cabinet, sometimes located on the bottom, next to the reverb tank, sometimes on the side.
The codes are usually handwritten, and the letters can occasionally be hard to decipher. There is no reliable way to date 2003-2005 amps other than to ask Fender customer support to look up the date from the serial number, although you may find a date code on the speaker.
A little light Googling revealed serial numbers for a few other amps in the range - they seemed all mixed up together.
Then the terrible truth dawned on me: they WERE all mixed up; Fender had decided to change their 35-year-old system of serial numbering so that, starting in 1982, every amp had a unique number.