1939 EK2 purchase. Is it legit?

[Ozbrit]

Hi all.

I've been lurking for a while and have now joined up.
So let me start with the standard beginners question. Is my Iron Cross legit?
It is of 3 piece construction with a magnetic core. The core doesn't rattle, but I can fit the corner of a piece of paper between the frame and core.
There is no makers mark, the ring is soldered. There is a neat join down the edge of the frame. It is 43.5mm wide.
The black finish looks matte in real life. I have added scans, daylight photos and cheap desktop microscope photos to try and cover all bases.
What do you guys think?
I have the opportunity to plead my case with the seller. He's a legit dealer that has been in business for decades, some people don't like him though.

There are things that worry me, but I don't want to pre-empt. 
All opinions appreciated.