Know nothing about the origins of the dog house other that it was there. Nice condition! I helped Roger Briggs a little (very little) when he rebuilt some of the dog houses on the C&TS
Tender swapps on the Big Ks were not near as often as the smaller locomotives and pretty well documented during operating times. The 37 tenders were pretty distinctive and you can track them through pictures. 497 getting the 490 tender being one of the notables, then the cistern being rplaced on the D&S. Upon their dispersment, tenders moved around a bit since the Grande was short a 37 tender