I know that laws can vary tremendously from state to state, which is why I want to ask this question:

  In California, the county-by-county records index is established by State Code.  That code allows the individual Counties to choose whether they use a General Index wherein all records are included, or a Book-based index where seperate books of Deeds, Mortgages, Lis Pendens, etc.. are used to record the documents.  It does NOT allow the county to switch, in either case, to a non-name based index system of using parcel designators.

  How was this accomplished in Orange County, North Carolina?  Is the NC law in it's original form, something that allowed this?  I doubt it, as most "Assessors Parcel Number" systems are of recent form (about the 1960's or thereabouts).  As such, I would guess that some new Code was passed which allowed for the Counties to do this.  Any insight would be fascinating.