Fragony's post here is the third link on Google when you search for "Meinfeld AK-47", so there goes my attempt to find anything about that...

What I can find are theories about Hugo Schmeisser having developed the rifle instead, the Moscow Times calls it a fringe theory however, while the only sources claiming that Kalashnikov admitted that Schmeisser did it are apparently blogs, like this one.

Of course both sides have an agenda, some people hate the soviets and do not want to attribute such a wonderful rifle to them or they just love the Nazis so much that they do not think Russians were capable of coming up with anything decent (which is wrong of course). On the other hand the Russians wouldn't just admit if a German engineer helped design their iconic rifle just as Americans like to forget that they needed German technologies to get to the moon and to break the sound barrier.

Quite frankly I don't think it's important, I find it far more debatable and worthy of debate whether the development of that rifle or any other weapon is a good thing that ensures peace or makes one indirectly responsible for all the deaths this weapon causes. To me this doesn't seem really clear cut. Unless one considers the unlikely option that all humans would stop developing weapons, someone will always make the tools to kill people anyway, so why wouldn't he try to give his people an edge? What seems far less moral is giving them to shady people for money but even that seems inevitable.