The main reason you don’t see many photos of drop bottom gondolas on the RGS was primarily due to the fact that there were not many receiving locations where a load could be dropped. All the RGS company coal had to be hand shoveled into coaling bins at Vance Junction, Rico and Ute Junction while at Ridgway they simply shoveled directly from a gondola into the tender. The D&RGW had coaling towers at many of their terminals which saved the labor of hand shoveling coal from the car to the storage bin.
Dorman has photos in each of his RGS books of trains with drop bottom gondolas while the attached pic from Otto Perry shows one as well. These occasional loads using the DB gons were most likely cinders or fill to be distributed on-line for MOW purposes.
Otto Perry/ DPL photo OP-8103
D&RGW 464 & RGS 20 helping NB on the RGS near Durango, CO with 24 cars