Boiler replacement on C's

It is my belief that the replacement of boilers on the older 2-8-0s in the teens is an "Urban Legend" among narrow gaugers. Some "expert" was asked about the extended smokeboxes you mentioned and his pontifical answer was that the boilers were replaced. Pigfeathers. New extended smokeboxes with internal spark arrestors were fabricated and riveted on to the original boilers in most cases. In some cases new smokebox extension rings were welded directly to the original short boxes. It would make no logical sense to replace boilers, what with newer locomotives on the property (K-27's) and more planned for the future (K-28's), and the plethora of surplus 2-8-0s that standard gauging and the advent of larger power had caused. You need a few small engines for light branches? Pick the best of the remaining lot and scrap the rest. Why replace boilers on engines that were being phased out? Basically, unless someone comes up with the records showing the purchase of new boilers and the work being performed I have to say the replacement of iron boilers with steel in the teens is a myth.