Just got old blue PF63 and new black PF63A cut open and compared side by side.
The PF63 was a shipping damaged one so nobody cares, PF63A I bought it, just for fun and out of curiosity.
Dispite being shorter, PF63A is heavier than PF63 significantly, for an oil filter.
Once cut open, the base plate and case are both heavier/thicker on PF63A.
The filter element got shorter, of course, and the PF63A has visible inconsistancy on plate gaps, PF63 is more even and uniform.
The bypass valve are different, cannot tell who is better, as long as they work as designed and opens/closes at the same pressure, it should be OK.
The anti-drainback valve are both black rubber I would assume, significantly thicker on old PF63, almost doubled the thickness.
Overall they are different but should not make a huge difference.