Well, I guess I will chime in here since I was intimately involved getting the 481 back in service in the summer of 1981.
* The locomotive was reasonably complete with the exception of various parts and appliances that were removed by the DRGW to keep the 3 K-28's in service. These included air pump, injectors, lubricators and various portions of the tender trucks. These were all easily replaceable as we started to receive various appliances and common parts from the DRGW Burnham shops in Denver.Many of these parts did have to be gone through and rebuild, including the air pump. I can't recall if we removed the entire jacket and lagging or just enough to remove and check the caps. (it was a long time ago)
* I do not recall any UT being done, and if so, it would have been done in the firebox area so as to obtain an idea on how it all looked. The flues were not removed.
* The D&S did have various records for the 481, including the FRA monthly and annual cards, still being maintained by the DRGW through 1980. With that said, the D&S was no longer under FRA at that time, as they were no longer a part of the DRGW system. All boiler inspections and requirements were done by the State of Colorado, even though that was uncertain in the early days as well.
The spring and summer of 1981 was crazy as we had to get all 3 K-28's returned to service and the 481 by the end of July. The inaugural run was made to the Iron Horse Resort on August 1, 1981, just shortly after it's very first fire up and shake down. These were both exciting and stressful times.