I have been told the answer to this already.But want to confirm with whoever knows about this on SON.
Question: Would a engine harness from a 1995 240sx KA24DE in California be the same as the harness we have up here on our S14’s? It might sound like a nobbie question but I want to make sure they are the exact same. 
thats in no way a newbie question. Cali is more strict on emissions. I wouldn’t be surprised if there were some minor differences.
I agree with Andrew there are likely to be some minor differences Emission’s is a key area to look.
However depending on what you plan on doing with it you could either modify the harness to work (it would probably work anyway, so modify it to work properly might be more accurate)… or if you just wanted to use it for a SR swap to send off with the SR harness… then it would only be important that the portion they use is the same. That portion would only be the wiring for the wiper motor and amplifier, ABS stuff, plug for dash wiring etc. (might have missed something, but your get the drift). I don’t see there being any issue if this is your planned use.
-Martin.