Alright, so I want to the only dealer of bareknuckle pickups in my country and bought a set of warpigs from him, also bought two potentiometers from him wich should be standerd 500k CTS potentiometers, BUT I just checked the two potentiometers and one of them does have 500k on it but the other one has only this on it: "450S3325A 1004 CTS" .
Also, the top end thingy on wich the knob has to be put on is double the length of the that thingy on the 500k potentiometer.
I bought two of the BKP custom 550k pots, and they both have exactly that on them. However, mine are the same size as a normal pot - so maybe you somehow ended up with one of those but in the long shaft version (either that or I ended up with the same weird pot as you..)
Correction: On comparing the pots with the other pots I have here, I found that this pot
does have a taller top than a standard CTS pot...
The knob will fit if it fits on a standard CTS pot, but some knobs that are designed for the smaller (metric?) alpha pots will not fit.