Hi Jim
I can't say I've seen a photo of AM 52 with a white rudder. Looking at photos from Obertraubling it would seem that factory fresh manufactured parts were, from what is seen in black and white images, light in color therefore seeming to be white. You do mean the full rudder.
Or do you mean the band of white on the tail?
See the link below for photos of white rudders.
http://s262.photobucket.com/user/Dug...bling.jpg.html
KR
Vince...