Having restrained myself on the green boiler issue so far, there are three excellent sources for photos of the K class engines in the 1920-1950 era available. The first is Dennis O'Berry's book on the Mudhens, and the other two are volumes 1 and 11 of the Bob Grandt's Narrow Gauge Pictorial.
In Dennis Book, there are pictures of:
#453 in 1939, and in 1951 in which the boiler jacket is not black, but lighter color. In addition, the 1951 photo shows the cab panels painted in the same lighter color, plus a very liberal use of aluminum paint on the engine. Both of these pictures were taken in Montrose.
#454 also shows up with a lighter boiler jacket in 1930 in Alamosa. A Montrose picture taken in 1937 shows the locomotive in what appears to be the weathered version of the same paint.
#455 is photographed in Alamosa, also in 1930 with the lighter color boiler jacket and fresh out of the paint shop.
#456 is photographed by Gerry Best in Gunnison in 1936, with what might be a lighter boilder jacket.
#459 is in Alamosa in 1939 with a light color boiler jacket, and fresh out of the shop.
#461 is at Salida in 1936, with what is identified as a "fresh Alamosa green boiler paint job" in a Gerry Best photo. On the next page is another photo of 461, taken by Richard Jackson from a different sun angle on the same day and the color distinction is lost (but the tender herald looks interesting!)
#462 is found on in Alamosa in 1940, carrying a "green" paint job on the boiler. Photo from DeGolyer.
In Narrow Gauge Pictorial Volume 1, we have the following:
#473 in Salida in 1931, with a lighter color jacket, darker domes and cab
#482 in Durango, 1933 with an obviously lighter jacket, compared to the rest of the locomotive.
The pictures of ##477, 485 and 487 appear to be a very weathered version of the same scheme but is is a stretch to get there.
And in NGP Volume 11:
#456 in Gunnison in 1940 with what appears to be a lighter color jacket
Again #459 in Alamosa in 1939,
#461 in Salida in 1938 and Montrose in 1939
#490 in Alamosa in 1938
#493 in Gunnison in 1937
#498 in Gunnison in 1941 and
#499 in Salida in 1937
Other "green" photos exist of:
#489
#497
All of these engines were painted last before the flying Rio Grande, with the exception of #453 at Montrose in 1951 and we all know that the 340 and the 605 both at Montrose were painted green at that same time.
It looks to me as if most of the K-27s, and K-37's got "green" paint at least in the last repainting before the flying Rio Grande and the big cab numbers, and at least one K-28 and possibly more than 1 K-36.
Yes, we all remember them as black but to paint one green is certainly not wrong, and clearly represents the depression era which molded the look of the narrow gauge that we all (those of us in the post WW2 group) remember.
I would say the I got my 2cents worth on this post, but it would have to be a depression era 2 cents!
Happy Holidays to all of you out there! Keep up the friendly discussions! Reading the NGDF helps me get thru the day, every day.