Maybe this thread will help...if not Paul will have the answer.
http://photo.net/medium-format-photography-forum/00Fv5d
After reading this and finding another screen in a box as part of the sale I can definately see the difference in brightness. The darker screen is heavier and has cross hairs. While the brighter screen is an Acute Matte it doesn't have the notches so it must be the non-D version. Thanks for your help.