Hang on, just watched the video again.
Every other video I've seen of the n4 shows it with a silver bolt, that video shows a black one with noveske logo.
The black bolt is what I have in my n4 I bought last weekend. If I'm right and I have the "newer" version.......efficiency isn't great from what I've experienced. It'll do a whole mag on semi but definitely felt like it was getting sluggish, but won't do a mag on auto.