Josh, I don't buy that one, but you had me for a minute, there. I looked at the picture, I think the shine on the boiler is reflecting some color from the sky, which gives it sort of a weird tint. Find another shot with a green jacket I'll buy you a cannon shell casing full of your choice at the Dead Goat.
The Bumblebee scheme on 473 had black jacketing same as 268 I am quite sure. I think. I mean I think I'm sure..... I've seen lots of pictures of 473 in that Bumblebee scheme, and I never thought the boiler was green.
The picture does do a good job of making the case that it is really hard to see green jacketing in pictures. By the way, do you notice the brass bands on the domes? 473 carried those brass bands, still very much in evidence under black paint on the sand dome right into the Bradshaw era. Modelers take note! It makes a nice "extra" detail, depending on your period.
Mike