Update : I also Noticed Christian updated his 5D evaluation (I was looking for QE data for the 5D) with some test notes on the D200 and mentions the presence of the same 'median' type filter as per the D70. The link is:
http://astrosurf.com/buil/5d/test.htm
Gama, I reckon you should try to verify this yourself in the raw files you already have. If it is there then perhaps it should be mentioned to Nikon that this undesirable for scientific applications, and maybe they might release a firmware update.
Terry