I read somewhere they began producing the internal locks in 2006 but could stand to be corrected. I did not know that they were discontinued in 2012...
FWIW after owning several Old Model unconverted Blackhawks, I took the plunge and ordered a NM in .41 Mag. After I had placed the order, I read about the lock that and went into a spiral. I have never owned a revolver with any type of internal locking system. LSS, I received the revolver...