I'm sorry, this is a fake badge in my opinion. I don't know about the case but I have a feeling this is also not an original piece.
The badge appears to be a cast piece with soft and poorly formed details. The reverse hardware is also wrong.
Looking for LDO marked EK2s and items relating to U-406.....
Fake badge-fake case
"Much that once was, is lost. For none now live who remember it."
Good eye gents.
[h=3]e plu·ri·bus u·num[/h]
Both are fakes for sure.