The 484 still had that tender in 1938 but it was with 488 by 1952. D&RGW records do not indicate a swap.
All the K-36s were built so that a flanger could be added in the future.
From the D&RGW/Baldwin specifications...Provision to be made for future application of Priest Snow Flanger as shown on Railroad Company’s prints 8310-L-345 and 8313-L-145, showing spacer block back of bumper beam, except that in arranging for future application of flanger, provision to be made so that flanger can be applied without use of the spacer blocks.
484 got her Priest Flanger in October 1940 and the Brakeman's Cabin (dog house) in January 1935.
All of the changes and additions to the K-36s will be detailed in the K-36 book I am close to completing for White River Publishing. Should be ready for sale by early summer.