All liens in NC are filed with the Clerk of Court and are in the Clerk's records.  You can only search there records by physically going to a county in NC (system has all NC counties) but if you need to look at a file you have to go to the county where the lien is filed to pull the file and any documents.  You also have to check Special Proceedings in NC.  

Also, NC is an "opinion" state meaning that only a NC state bar certified attorney can render that opinion for a title commitment and title searches have to be "supervised" by an attorney.  So with regards to NC searches, your client has to be a NC attorney.

 You can do document retrievals but as stated above, you have to be physically there to do so or find in independent searcher that covers the subject county.

Hope this helps.