The "Blonde" and "Brown Tolex" Blues Juniors feature traditional Fender Tolex upholstery in their respective colors, while the Sunburst Ash edition features an ash cabinet with a sunburst stain.
One edition was issued with a forest green colored cabinet, had a United States flag on the cloth speaker grille, and had United States Air Force markings detailed on the cabinet in yellow.
Fender frequently releases limited editions of the Blues Junior.
All have the same electronic components and specifications but have cosmetic changes and often a different speaker, at varying prices.
The cream-colored board is laid out entirely differently from the green board. The older amps tend to sound darker, while the new ones are brighter with more emphasis on treble tones.
The standard Blues Junior is dressed like a traditional black Fender amplifier, with black Tolex upholstery and a silver cloth speaker grille.
Although they differ in their external visual aesthetic, all variants of the Blues Junior for a given year are produced with the same electronics, apart from the speaker/driver.
While doing research on Fender amps in general, and the Champ in particular, I came across the most amazing series of articles by Greg Gagliano on the subject. If you have any interest in vintage Fender tube amps, without question you’ve got to read them all.
The process that went into figuring all of this stuff out over 6 years and countless owners of vintage Fender amps is hands down an amazing story.The codes can be handwritten, which can occasionally make the letters 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.