I wouldn't worry too much about the knuckle knife.
They seem to have been made by more than one company in WW2.
Especially in the private purchase versions.
I don't think they all had the BC41 mark.
Pattern goes back to WW1.
No manufacturer's mark?
They say the universe has been here for something like 13 billion years.
And what do I get?
A lousy three score and ten!
I guess I must be using someone elses' leftovers, now.