2006 amps have a small metal “Fender 60th Anniversary” button on the back plate. Early Tweeds The early green board tweed-covered amps were not lacquered. It has the same cream board inside with the same components as every other current-production Blues Junior.
The serial numbers for these amps begin with “LO,” indicating that they were made in the Fender/Sunn Lake Oswego factory. It usually applies to old vacuum tubes/valves that have gone unsold for decades. All cream board tweed Blues Juniors have a “Limited Edition” plaque on the back.
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.
These are rough guidelines to help date your amplifier.
Stock Speakers Outside the chassis, Fender has used several different speakers in some Blues Junior models.