I am considering purchasing this helmet, but am wondering whether it is a completely authentic german stahlhelm, as the seller claims. It is a Quist m40 helmet, with the size stamping on the back of the brim, and batch number on the side. I read somewhere that it was first after 1943 that Quist started stamping the size of the helmet on the back, but the batch number was also stamped on the back right above the size. On this the size and batch number are two different places, is this a source of concern?
In addition, the name of the owner is etched in the helmet, not painted on as one can see on many other helmets.

Are the rust pits (there are not very many, but certainly some) a sign that it has been laying in the ground for a number of years, and later repainted?

Would be very grateful for any thoughts on the matter!

Click to enlarge the picture