First aid kit Luftwaffe: Question about license plate

[Dickdan007]

Hello, I finally have mate first aid kit, I waited a long time. Everything is right and perfect.
I have a question about the number plate (from a car where the box was on?) WL = Luftwaffe. But does a "K" come after that?

I am looking forward to hearing your opinion.
thanks

[Dickdan007]

But the 2 first letter can be: 14 (146440)