Robot Luftwaffe camera

[marmion1]

Hi, I am looking for help in valuing this camera.
The camera is in a used condition (WWII). The camera does not appear to be stamped as Luftwaffe but the serial number is F 57608-6 which indicates use by the Luftwaffe.
The Robot has one cassette. The clockwork mechanism and the lens shutter are working.
It looks to me from pictures of other Robot cameras that the top knob is missing, this does not stop the mechanism from winding up.
The back of the camera has not got a badge but has Robot engraved on it.
The bottom plate is brass which has been painted black.
The lens are labelled
'Schneider-Kreuznach Robot Tele-Xenar f:5.5 F-5cm'
As you can see below I have not attempted to clean the camer.

 

[hearts0075]

Do you have a local camera vintage store in your hometown that can help you at all, about its value?