This is the German rangdefinder model with the film advance lever at top left.   Removal of latter is straight-forward.  But the RH side of the top-plate is being held obscurely.  
There are three possible options and if I get either one wrong - someth

Remove the spring clip around the film counter and lift the counter plate off. There is a screw underneath.
 
I have a repair article on this camera on my website:
http://daniel.mitchell.

 If you're in need of a donor camera check my  
recent posting in the swaps.

Daniel ...
 
I express my respect and admiration for what is one of the best camera-service webpages I have ever seen.   Others who may not be particularly interested in the Iloca  - might do well to see a very carefully engineered knowledge-transfer

 Dan,
 
I wanted to add another thanks for your fantastic site! One of the best step-by-step repair pages I've used... Got the (seemingly impossible) job done in a matter of minutes following your instructions!
 
Thanks again!
 
Peter