Hi Richard,
I have been reading this discussion with interest. Being a modeller and Australian - I try to keep an eye out for information on 'our' 163. Unfortunately it has been in Canberra ever since I remember and I'm in Melbourne so I haven't had a chance to look at it in its current state yet. If you haven't done so, you should check Rob de Bie's fine Me 163 site. There are many photos and extensive notes on all the 163 survivors with colour notes. This page is on the AWM 163 and gives a history and period colour photos of the aircraft.
http://www.xs4all.nl/~robdebie/me163/australia.htm
Somewhere on cd's or my old pc hard disk I also have some pre 'restoration' colour photos of the 163 taken by John Hopton on his now closed website. They are different to the ones posted on Rob's site but may/may not add more detail - Colour photos seem to be affected by the film type/lighting conditions and I have seen different photos of the AWM 109G showing dramatically different colour appearances based on what lighting was used (artificial/outdoor/cloudy/sunny)
Cheers
Michael