They are made like this, I believe this is the rarer type as most of them just have a plain filled in silhouette of the award. Without more photos it's not easy to say if it is authentic or not.
I've moved the thread to the KVK forum, try a search through here and you will see several types of case.
Looking for LDO marked EK2s and items relating to U-406.....
Adrian is correct, a scarce early designed box
"In all my years as a soldier, I have never seen men fight so hard." - SS Obergruppenfuhrer Wilhelm Bittrich - Arnhem
If both are real & at the right price? A nice a little set there..I'm still hunting for a nice case in slow time like you do!! Cheers Terry.