I have a bit of ref material on the Arrow.I have a book called the Arrow Scrapbook written by Peter Zuuring and published by Arrow Alliance Press (1999) ISBN #1-55056-690-3.
It's a great book for any Arrow lover.It has several pictures both period and some current colour ones of several artifacts including the nose section of RL-206 that is preserved at the National Aviation Museum in Ottawa Canada.From the pictures I have,it appears that most of the interior was painted a light grey with a slightly darker grey instrument panel(it may be the same and just the lighting makes it look darker but it's very close).All of the switch panels seem to be flat black or a very dark grey(much like old tires).The control stick is chromate yellow with a black handle.The throttles are completely light grey and do not have black handles as one would expect.There are several areas below the instrument panel and behind that are chromate yellow.The floor is also chromate yellow that has been painted over with grey.In the pictures I have,the chromate yellow shows through the grey with almost no bare aluminum showing where it has been scuffed from use.This section saw a fair bit of use while it was in service with the Institute for Aviation Medicine as a low pressure test chamber.Through out most other areas such as the weapons bay,dive brake and flap interior and most interior structures,chromate yellow is the predominant colour.The engine intakes are also chromate yellow with only a rubber de-icer boot at the inlet.
I hope this helps you some if you can't find a copy of the book.I'll see if I can find someone with a flatbed scanner and get you copies of the pictures I have.You could also try the website for the Arrow Alliance at www.arrow-alliance.com to see if there are any good colour pics for you from the book.
Good luck with the build.
Kevin