The potentiometers, or variable resistors that are turned to vary the volume or tone, have codes on the back that indicate the week and year they were manufactured.
Let’s look at the control cavity of this 1967 Gibson Melody Maker D.
On this guitar, the top two are volume and tone for the neck pickup and the bottom two are volume and tone for the bridge pickup.
There are a few sets of codes on the back of potentiometers.
That’s all I can make out from these potentiometers so let’s try another. Here we have the control cavity of a 1965 Fender Jazz Bass.