I have checked Wikipedia as well as my uni psych textbook, both say it goes from 2 to REM.
However, I remember being asked a question about this, and in the 2010 exam, question 37 --
http://www.vcaa.vic.edu.au/Documents/exams/psychology/2010psych1-w.pdf, the only possible correct answer says that it goes 2-1-REM.
I've always believed it to have skipped N1. Although, if you look at the graphs that are going around, where the y-axis has N1 is where REM begins

Bit weird.
VCAA have been known to distort answers from what they actually are for whatever reason so I'm definitely not taking the word of the 2010 exam

, however, it perhaps sheds some light for you guys as far as VCAA expectations (although, they've been inconsistent in the past, I know the 2013 IT: Apps exam had an answer directly contrary to a past exam). I think Stage 3 and 4 are just referred to as N3 now
Pretty interesting really, I will perhaps later try to find some journal articles that are unanimous one way or the other and report back.
Interestingly, this link here
http://healthysleep.med.harvard.edu/healthy/science/what/sleep-patterns-rem-nrem shows a graph through sleep where N1 isn't present - perhaps to avoid the confusion we've already had? I'm leaning towards maintaining my answer.
Edit: Chief assessors don't actually make the answers. The assessors collectively make answers during an assessor's meeting. The CA's role is to instruct the assessor's how they ought to be marking, as well as to review what marks assessors have given what answers to ensure consistency and whatnot.