http://cgi.ebay.de/RARE-MENS-OMEGA-CONSTELLATION-MINT-ORIG-BLUE-DIAL-DATE-/270604411643?cmd=ViewItem&pt=Wristwatches&hash=item3f0147a2fb#ht_786wt_913
I have the same watch, no caseback, movement is installed from top, like ploprof 600.
maybe it uses the same stem like ploprof 600 ? any idea ?