"IK" on registrationplate on motorcycle

[Jules]

Dear Sirs.

What is "IK" on a motorcycle egistrationplate?

In George Forthy's "Germany at war" on page 104 there is a picture of a german dispatch rider i Bulgaria. The registrationplate on his motorcyckle reads "IK 132 063".

Anyone knows what "IK" is?

Regards
Jules

[Jules]

Problem solved

Dear sirs.

It seems, I have solves the case myself.

My studies have shown, that IK is a civilian registrationnumber from Sigmaringen.

Seems like the military used civilian motorcyckles.

Regards
Jules