Off the top of my head, I can't put a specific NEC Article on it, except 110.12 regarding mechanical execution of work.
However, this Article is basically unenforceable as it is 'subjective' as to "neat and workmanlike manner".
Your comment regarding the connector/locknut not being flush with the KO goes back to NEC Art 250 and a 'stretch' would be NEC Article 110.3 (B): re. mfg install instructions.
Last edited by HotLine1; 06/04/16 11:59 AM. Reason: add comment