As for GPS, yes. I understand the V1 GPS has problems and that DJI would replace it. I got V2 right off the bat.
As for IMU, V2 refers to the EVO version which isn't plastic anymore, and that you have to buy if you want it. I fly with the original IMU.
No, I got a good V2 GPS right off the bat, and mine says "GPS/Compass V2" (http://www.dji-innovations.com/wp-content/themes/dji/store/products/gallery/wkm/wookong-m_gps.jpg). My dealer says that V2 is the latest good version of the GPS, and it's what's on the DJI website. I had read somewhere that there was a recall on a earlier version (I presumed V1) that was being replaced by DJI (but I wouldn't know first hand).
So I'm equally confused as to how to identify a good GPS or not.