I had the pleasure of being published in the Zouki Mura ‘Old Man’s Blog’ some years back, featuring the 229 built to replicate what I thought the prototype could have looked like before it was ‘captured’ by the American forces, painted and shipped back to the USA for back engineering.
Using the wood grain decals by ‘Uschi’ of Germany, before they were included in the kit at a later date.I submitted my build images to the manufacturer and it was finally used as promotion material, focusing on the wood grain decals.The Old Man Blog No.062 - Presentation of the finished SWS Horten kit!! | ZOUKEI-MURA . Something I am very proud of, as every modeller after that copied what I had done with varying results.The Old Man Blog No.062 - Presentation of the finished SWS Horten kit!! | ZOUKEI-MURA I posted the complete build on ‘Scale mates’ if you care to take a look. Zoukei-Mura's "Wood grain" Prototype Ho-229 () by RedRoo - Albums Cheers. 
I’ve got this kit in my stash, and I’ve been watching the conservation being done on the V3 since it was moved from Silver Springs to the Udvar-Hazy Center, picking up little details as they’re uncovered. One of the things that interested me was the greenish coating on the interior of the skin panels, presumed from its composition to have fire-retardant properties (see ‘Technical Study of the Bat-Wing Ship’, section 5.5), ; the existence of the coating wasn’t known at the time the pre-production models were built for the Zoukei-Mura promotional photograpy, so in the underside shots of the built model(s) you can see what looks like bare wood surfaces. And I’ve spent more time scouring the net for pictures and descriptions of the complete configuration of the Jumo 004 engines, specifically details that would have been impractical for a mass-production kit, even with the sometimes absurd level of detail that Zoukei-Mura puts into its kits, like the wiring harness on the left side of the compressor stage and the minor piping on the right side.
When the Ho-229 was ‘captured’, it was spray painted the color you see in the images from the Smithsonian you see today. No one really knows what the colors were going to be from the German side, so, what the Americans did was ‘guess’. But the Germans did use zincchromate on exposed metal areas on all their aircraft, just like the USA did too. As for the wiring loom for the engine, I am not aware of anything from the ZM mob so I would do your best to see what other images of the Jumo used on the Me 262.
Outstanding work. Really fascinating subject matter. 
—mike
What Mike said. I think that considering it was only 40 years since the Wright bros. first flight, the 229 was a mind-boggling leap into the future. Apart from the revolutionary design, Reimar Horten claimed in 1983 he was working on stealth technology (during WW2) to make the 229 invisible to radar – studies since suggest it wouldn’t have worked, but nevertheless we’re talking 80 years ago! I’ve always thought that if I ever go back to aero modelling, a scratch-version in 1:16 scale of this amazing design would be my final work.
No, I’m referring to the color of the inside of the skin panels, which weren’t painted after it was captured:
The promotional images from Zoukei-mura’s ‘Old Man Blog 58’ show the inside of the skin panels as bare wood (or a clear finish):
The top image is one of the belly panels of the V3, which would be the panel under the engines; from the position of the cutout for the nose gear, it should be the right belly panel. There is no information in the report about the interior of the panels elsewhere on the aircraft, but it does say that the coating was found in the areas around the engines – the inside of the belly panel, and as an undercoating on the upper surface behind the exhausts under the paint layers and metal sheathing.
My apologies. I did misunderstand. It is still a mystery to this day about what it actually looked like back then, and many modellers did take artistic license when painting their models defaulting back to the way that most German aircraft were painted during the war.
Just like I did when I went with the idea that how the ply wood would have looked before real production started, as there were more carpenters than metal workers in Germany at the end of the war and wood was the most plentiful of all the raw materials available, having seen their factories and smelting plants destroyed by the allied bombing.
Just closing the circle - Kerry’s reply to me above was for you 
Given the running shortages in the late war, I would expect that the green interior coating would only have been used in the center body, where the plywood was exposed to the hot engine or exhaust, both as a reduction in expense and in the time required to coat the inner surfaces of the wing sections – pictures 02 and 04 on page 48 of ZM’s book on the Ho229 appear to show the interior of a wing section with the skin in bare wood and the framing in RLM02, but the accumulated grime makes it hard to say for certain. And the one historical picture – 03 on page 36 of the book, showing the extreme rear of the center section without the upper skin, has the wood framing and inside of the skin relatively bright compared to the internal metal framing, which suggests that that section of the skinning didn’t have the coating – but as it’s a B&W photograph, comparing its shades against modern photographs of panels with 70 years of dirt and dust accumulation is chancy – one picture of the inside wheel well cover could stand up against the ‘black plastic BMW wheel well liner’ photo in the early-war camo thread as exemplar for how grime changes colors.
