Minnesota adopts the NEC, as you say, lock, stock and barrel. Having worked primarily around the seven county Metro Area of Minneapolis / St. Paul, I've found that the modifications to the NEC pertain to existing structures wired under earlier codes. These modifications are done at the local level - city and municipality and are published in numerous places.
From the questions raised here and at similar NEC forums, it is apparent that reasonable minds will interpret the language differently on occasion. The State of Minnesota Electrical Inspectors and the Minnesota State Board of Electricity are no exception to this.
The licensing exams are administered by the State Board. The test, in my experience, was on the NEC, not the local modifications to the NEC. [b]The State Board Code Interpretations[/b]
are mostly linked to on this page at the State Board web site.
IMHO, bone up on the NEC and you won't go wrong.