OK, then, although this is not exactly on topic, I mentioned it before.
The boilers from D&RG #42 and #283 (not #286) were apparently swapped at some time prior to 1887.
According to the CRRM publication "Steam in the Rockies" the information in which apparently came from the original R&LHS roster, and was added to by many historians, #42 (with the boiler from #283) went to the Sliverton as #100, and in 1933, 286 with the boiler fromo #42 (as verified by Gerald Best) went to NCNG. The information used at this time apparently reflects the locomotive number as being the frame number, not the boiler number.
However, if the boiler number is the correct locomotive number, then #283 actually became Silverton #100 and #42 became NCNG #8.
We live and learn!