difference between CA VX and lean burn VX

[GasSavers_James]

Hi,
It will probably sell before I can go look at it, but there is a VX for sale. I was wondering if anyone can tell me (I think i read it once, but i searched and couldnt find it) how to tell the difference between a california VX that doesnt have lean burn and the lean burn model? Is it that the lean burn model has a 5 wire O2?? Also, to detect lean burn mode what wires do you hook the digital voltmeter to?
thanks,
James