Folks,
If you look at the hi-res scans which have been uploaded either on David's "Falcon's Messerschmitt Bf 109 website or on my Flickr account, you will notice this machine displayed it's full W.Nr. under the "Weisse 81" on it's rudder... The whole issue is to read it...
http://www.me109.info/display.php?a=e&fid=7194
http://www.flickr.com/photos/2809206...in/photostream
As for your point 4), Rémi, this is the normal Flossenbürg camouflage scheme, with the Balkenkreuz filled by the dark color.
Cheers
Marc