Hi Guys, as I have a few of these in my possesion at the moment I thought that you might like to see them?
The first, although the condition is not briliant, is a fairly early one and is marked "MKb42 u. MP43".
The blueing on this (and all the others I will show is original) and in this case is just the same as you can observe on early MP38/40 submachine guns. It has a blue/slate grey look about it, where as some later ones are much more black in colour.
This one is made by "fxo" C.G.Haenel, Waffen- und Fahrradfabrik, Suhl