They all had (except in some instances like on the RGS 455 that had a 5-Chime) the common standard D&RGW Hooter. Just like on 463. I believe the Rio Grande produced their own whistles or had them made somewhere else but they had D&RGW cast into the side of the valve and on top of the bell of the whistle. Some of the early ones were brass and later cast iron. If they weren't delivered with them they were put on soon after by the Grande.
The hooter was the Rio Grandes freight whistle and in later years the passenger engines had 5-chimes.
Bush