Great job have been following your progress that was fast work. Amazing you got the decals so fast. The real British Columbia Railway caboose were first painted with Silver roofs as was the Atlas factory BCR caboose but over time many of the real cabooses received the black treatment so this is correct. Great job that you did, now you need a few of the matching freight cars.
Would you be able to post a photo of the engine beside the caboose to see the color difference. I am painting up an old RS3 dummy engine to go with my Atlas RS3 and have been tinkering with the BCR paint colors by Rapido and Trueline trying to match them up with out success with the Atlas BCR colors the dark greens look good but the light green is not a close match as you had noted with the paint you used. I took the Atlas engine to a household paint shop and got them to do a digital scan color match and got a pint of green that was fairly close but could not get it to spray. Tried brushing but can not get it very smooth.