Jack Thode made a list of the origins of the water cars from the railroads records. He shows the original water car W481 was converted from an engine tender in 1924.
He notes that the original car was worn out and replaced in May of 1936. He notes the tender came from Locomotive 206 and this does correspond with the scrap date on the #206.
The many pictures of 206 I have are much earlier and show that loco with a collared tender instead of this winged tender. But tenders were swapped many times.
He notes it was used out of Salida. There is a picture of this tender as a water car in Gunnison 1940 but you can not read the number as only the the rear half shows. Thode list this water car being retired in Salida October 1944.
The info I posted above comes from drgwcarman (I believe John Templeton) He said it comes from D&RGW records.
He shows the cistern from W-481 was placed on #06204. Another post shows this being done at Salida in October 1944. He references "destroyed car file 5183.
There is a 1955 picture of this cistern on the 06204 in Durango. It clearly even shows the burn marks that are on the 09410 cistern in early Chama pics.
John then records This cistern being removed from the 06204 and put on the 09410 at Alamosa August 24, 1957.
There is a very interesting 1928 OP pic of the #319 in Salida with a very similar tender cistern. The only time it is seen with it.