The POLLY Scale colors for the D&RGW Buildings is correct.
Back in the late seventies I asked John Maxwell what color the Rio Grande painted its buildings.He said that he did not know but would find out.The information John got came from Jack Thode.
The structures were D&RGW Building Body Color
(Kolher-McLister 6-C-14 Jersey Cream) and D&RGW Building Trim Color (Kolher McLister 6-C-47 Brown).
I contacted Kolher-McLister,they no longer exist,and was send original color cards for the building colors and also for D&RGW Freight Car Red(Kohler-McLister KM-91 Box Car Red)that was supplied to the Rio Grande.
Floquil colors 414255 D&RGW BUILDING CREAM ,414256 D&RGW BUILDING BROWN & 414258 D&RGW FREIGHT CAR RED were matched to the original Kolher-Mclister color cards.
The D&RGW freight car parts that I have also match KM-91.I hope that this information helps.