I suspect that this might be one of the gons (or the only gon) modified by the contractor for ballasting the new trackage around the Navajo Dam project in the early 1960's. The cars were returned to the D&RGW and for several years sat in the north yard up near the Strater Hotel. As I recall there were two Drop bottoms one with modified doors to dump toward the center of the track, and one Highside modified with wooden slope sheets into a center dump "hopper" car. Cant help with the number as the photos I have of it show it numbered X952. I believe that some of the other cars Had a "Z" prefex. Car X952 was a nine stake car if thats any help in IDing it. If I can figure out how to post a photo I'll give it a try.
Dave G.