Easyscor,
The original Nine-0-Nine was painted in early-war OD, which is very 'brown' ( actually yellow ), versus the later war OD, which is very 'green'. Later war OD can be so dark it looks almost black on new aircraft.
The Collings bird is close in hue to the original color, but as you mentioned, the WWII paint is flat, not gloss, and I think the original color is a bit darker.
Your original post looks great and is a really good match for the later-war color.
When it comes to camouflage, close is good enough. Paint batches do not match exactly, sunlight and weather fade the paint, repainting is done in the field, etc.
Also, the color in a photograph may not be true because of the developing and printing process.
Now that I've started the "what color OD really is" argument, I'll sign off
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