switching Hot and Ground wires , change sound?

If you swicth the hot and ground wires on a pickup for whatever reason (phase correction etc)

1 .does it change the sound of the pickup ?
2. If so , how does it change the sound and why ?

Im talking 4 wire pickups here , i understand the ground issues when doing this with a single conductor pickup

p.s has Gibson ever changed thier wiring code or has anyone ever had gibson pickup with un-standard gibson colour code?

With 4-conductor it shouldn't change the sound. I don't think you will have any problems.