Thanks a lot for those findings .
The Ju 52 floatplane of Legion Condor is indeed a rare bird ,but, here ,it is very special :
http://cgi.ebay.de/ws/eBayISAPI.dll?...m=200206268171
-It has got 2 dorsal gun positions
-The rear one seems to have a cannon .
-The front one looks like the Ju G 1 or Ju K 30 dorsal gun position