Since several models can share one chassis type (for example, the early brown 5G7 Bandmaster, 5G5 Pro and 5G12 Concert), this kind of interpretation is inaccurate.
Instead, there were approximately 2000 of these chasses produced, which then ended up as one of the three models in question.
The following chart, was originally printed in VG magazine, by Gerald Weber.
If you see any data that is not listed here or notice any errors, for 1970’s and earlier Fender amps, please send us an email and we will update the chart.
Other things to look for include chasses placed in cabinets from a different year, “doctored” tube charts, non-original control plates (usually reproductions) on silverface amps, original transformer bell ends (they have correct date codes, of course) on non-original transformers, and non-original knobs (either repro or silverface knobs on blackface amps).unusual things can be found such as the empty “Pulse Adjust” hole on the rear of early ’60 brown amps, the “middle” volume control, use of tweed style grill cloth, strange non-documented transitional circuits, and changes in tolex color including the super-rare cream colored “brown” tolex that is found on some late ’60 amps. Given that people may refer to this information seeking specific production quantities of amps they are curious about, it should be pointed out that the serial numbers apply to chassis types, and not specifically to amplifier models.
Looking at serial numbers next to the ’60 5G5 brown Pro Amp for example, we see numbers ranging from 00001 to 02000, suggesting that there are 2000 of these amplifiers made in ’60.
Remember, your amp is newer than the newest component.
Neck-dating can be useful in determining the was produced, rather than the complete instrument.
Given the modular nature of Fender production techniques, an individual neck may have been produced in a given year, then stored for a period of time before being paired with a body to create a complete guitar, perhaps, for example, in the following year.
Therefore, while helpful in determining a of production dates, a neck date is obviously not a precisely definitive reference.
You also mentioned that you’re looking for a speaker option that decreases the overall volume of your amp.
Most notably, production dates have been penciled or stamped on the butt end of the heel of the neck of most guitars and basses, although there were periods when this was not consistently done (1973 to 1981, for example) or simply omitted.