The bikes with the Nikasil bores that got the mixed up rings were recalled and fixed by Norton almost instantly and almost before the owners could put any significant mileage on them! These were not the bikes discussed with oil issues which were 2010-2012 models. Norton did not ship Nikasil bikes till late 2013 and I know this for a fact! I have hands on knowledge of this not heresay!
There were only a few bikes with oil issues and some believe it was the owners checking and over filling the dry sump systems which have a completely different checking procedure!