Tom:
I think there were much less green boilers than most railfans and modellers would wish for. I had the opportunity to look at all the color slides taken by Dick Kindig (and he had photos of almost all of the D&RGW narrow gauge engines) and there were not that many. I think a lot of folks look at B&W photos and try to image green there when there might have been none. I think we would all agree that a K28 with a green boiler and a tri-color herald looks neat and a lot more appealing that a plain black engine, but the D&RGW was recovering from bankruptcy and did not have a lot of $$$ for paint, especially engines used in the boondocks of SW Colorado.
Do not know about 472 in green. The negative I have of 472 on the Shavano in the late 30s does not show a green boiler. My understanding is that green was used rarely on narrow gauge engines and there are almost none in Dick Kindig's photos. The D&RGW would use green on special Rocky Club trips and the Salida shops seemed to be partial to green.