I know accuracy is very important but it must be nigh on impossible to definitively decide the precise shade of brown and green; two photos of the same loco taken within minutes of each other could differ according strength of sunlight, cloud cover, etc. Not to mention the wide variations of colour arising from using Kodak, Agfa, Ilford of whatever other film, even between negatives and transparencies. Anyone who is lucky enough to have seen GT3 almost 60 years ago couldn’t be expected to have an absolutely accurate memory of the colour today. All credit to KR for asking their customers.
I remember the wide variations there were in BR blue, which was supposed to be standard.
As I never saw GT3, which was scrapped when I was a toddler, for me provided its not miles off I will be happy with it, I’m sure.