Well good luck. Maybe try taking them to a dealership to compare (if they have one on their lot). Note that the same named colors on other Nissan vehicles are not necessarily the same (dunno about the paint codes - I would think they are different). My dad has a new 2014 Rogue they say is Gun Metallic, same as my 2011 Z, but it is definitely a different shade of grey.
The PG is definitely the lighter grey of the two. Might even be able to fix out with a pic if the lighting isn't too bad.