Well I am answering my own question
I found this info under "general info and FAQ"
General model questions:
Q: How do I determine whether I have a 2001.0 or 2001.5 model year Pathfinder?
A: Check the manufacturing date of your Pathfinder on the driver door jamb. Dates 01/01/2000-08/31/2000 are 2001.0 model years; 09/01/2000-06/03/2001 are 2001.5 model years.
Q: What's the difference between 2001.0 and 2001.5 model year Pathfinders?
A: 2001.5 Pathfinders have revised spark plug coil packs to correct failures which plagued 2001.0 MY Pathfinders. Other than that, there is a newer smart entrance control unit in the latter half of the production of 2001.5 Pathfinders. If you're having a P1320 (ignition signal) engine code and have a 2001.0 Pathfinder, scroll down to the "Engine" section - there is a Q&A regarding possible fixes.