472 was damaged in 1944 and shipped back to Washington. Ultimately she was scrapped and the boiler went to the Ogden Utah Supply Depot.
The other 6 were returned to Ashburn, Washington and declared surplus in December 1945 by the War Assets Administration (WAA). The were offered for sale at auction and the winning bidder was M. Bloch & Co. They were scrapped in early 1946.
I assume that with the high WWII traffic levels dropping to peace time levels and the retooling for consumer goods such as automobiles plus the desire of the D&RGW to abandon the narrow gauge, the D&RGW had no need for 6 worn out K-28s that would have needed expensive overhauls.
The assumption that the US Army took the locomotives with no compensation to the D&RGW is wrong. They were sold to the WAA (although it sounds like it was a strong armed sale due to military needs) by the D&RGW. The 250s (I think) were offered to the White Pass first since they were already there. The White Pass passed on the offer.
Doug vV