It's a little-known fact that the position of the P pickup does vary across P/J's.
It seems to stem from whether the J is in the 60s or 70s position. If it's in the 70s, i.e. closer to the bridge, the P is 'correct'.
If it's in the 60s position, the P pickup is usually shunted closer to the neck to keep the distance between the pups the same.
If the J pup is in the 60's position, and the P is 'correct', they'll look noticeably closer together than you'd usually see.
IMO, that small amount of shift has a significant impact on the sound of the P pickup.