I have to agree with Scott. I would also suggest a Windsock Data File on the Spad for reference. There is more to detail out the interior. Also there is a Memorial Assoication In France which has several WWI ACFT Origianl Restorations on their hands and have great reference photos posted online. http://memorial.flight.free.fr/indexuk.html There are other things as well the Cross brace on the Inner Struts is a metal tube not wood. Also the Angled Forward strut on the Fusealage is a metal cover for wire braceing. The Windsock Data file has enough pics to figure out the raditor and engine plumbing which is missing from the Original Revel Kit but Hey even an OOB build of this kit is impressive.
The intruments are covered by CopperState AM PE Sets. as well as others just for this Kit. www.amug.org/~copperst
Some ask me from time to time which MK Acrylic colors for this bird and I refernece the WINDSOCK DATA FILE.
In reference to your Inquiry I checked Windsock Datafile 32 SPAD 13.C1 by J.M. Bruce.
Page 33 States " In October 1917 the French introduced a standardized five-color pattern for aeroplane upper surfaces, consisting of Chestnut Brown, Dark Green, Light Green, Beige and Black, with Light Yellow or Light Grey under surfaces."
Also on page 32, it describes the not as well known Yellow Camo Scheme. "The first SPAD 13's left the factory with clear Doped fabric surfaces, and the metal areas and forward fuselage, often extending to a vertical line behind the cockpit, painted a Light Yellow."
If your interested in the famous Five Color Camo Scheme I believe the Colors you'd want to Order are :
FR05 Chestnut Red Brown
FR11 French Dark Green
FR12 French Light Green
FR10 French Beige
Depending on the machine, unit, or service for the underside surfaces you'd want either:
FR03 Light Yellow
US02 U.S. Grey
The Yellow scheme would be:
FR03 French Light Yellow
FR04 French Clear Doped Linen
Let me know if you don't find what you want on ebay and want to buy one out right? I might be able to help?