Fender J Taper Potentiometers

[mresistor]

I recently noticed that Fender amps used J taper pots for Vol and Tone.  These pots reach 25% at the first half of rotation, then 75% during the last half.  I had always wondered about that on the vintage amps.
My question is "which Fender amplifiers used these J taper pots?"   Has Fender always used them? If not when did they start using them, and did they ever stop using them? 
for example https://www.tubesandmore.com/products/potentiometer-fender-1m-j-taper-solid-shaft-panel-mount

[pdf64]

I think most Fenders from 63 onwards used vol and treble pots with a taper of about 30%. As did the trem speed, but backwards 
Mid and bass were a 10% taper.
Around the mid 70s, all the pots were moved to the same taper, noted as ‘J’. The ones I’ve checked have been more like 30 than 25%.
The bass control became a hair trigger at about ‘3’.