Fender In the s, Fender mainly used potentiometers from the Stackpole brand. With 4 digits, the first 2 digits are the last 2 digits of the year. Some large parts distributors would even return parts if the date code was "expired" and want "fresh" parts in return. Note this is the same part number as the Stackpole pot above, although now produced by CTS.
CTS pot date codes
CTS pot date codes | Fender Stratocaster Guitar Forum
The Code on the tube chart of your Fender Amp is made up of two letters. The First letter equates to the Year and the Second letter to the Month. Reissue amps also use stamped Date Codes. Examples of "Hand Stamped" Date Codes. The source-date code on a pot is a 6 or 7 digit code impressed into the casing of the potentiometer. For speakers this code can be 5, 6, 7 or 8 digits long, and it's ink-stamped or paint-stamped on the "bell housing" of the speaker. In either case, the code works the same.
Dating stackpole pots
Since I primarily collect amps by Fender, and guitars by Gibson, Fender, Martin, National, Epiphone, Gretsch and Rickenbacker, I really can't help them with these other less popular brands. As you have probably noticed, there is plenty of information here to help date the brands that I am interested in. But where does that leave everyone else?
Early electric versions of Hofner models can be roughly dated by some of the components used. In particular, the rectangular and oval consoles were fitted with 'Preh' brand volume control potentiometers - "pots", which carry a manufacture date in code on them. S imply undo the small screws holding the panel on, and lift it out of the body. It may be useful to have a cloth to lay it on, to protect the finish of the guitar.