487 is currently in possession of 495s drivers. The drivers were swapped between 484 and 487 sometime back, although the precise reason has been, at least temporarily, lost to time. I suspect it may have been after the derailment of 484 plowing snow. It may be that the 487 needed new tires or other driver work and it was determined that it would be more expedient to use the set from 484 that were in better condition. Just speculation on my part though.
The discussion of interchangeability of rods and valve gear is basically correct in that all side, main, and most of the valve gear can be interchanged, with the exception of the eccentric crank. The one caveat being that there is some evidence that the D&RGW modified the combination levers on the K37s by changing the pin spacing similar to what was done to the 486. They will still work however.