It surprises me that no one has come up with 3-D printed GS gondolas of
railroads other than the D&RGW. Those two Rio Grande models are actually
quite nice; I've seen them in person.
Down at the local train store there is a Great Northern Ulrich/Walthers GS gondola in their used equipment case. The car's ends extend up to form heap shields atop the usual flat end with two horizontal braces. Is this model close to any GN cars, or did any other roads have cars of this design with heap shield ends? I'm tempted to buy it and do some upgrades, but not if the ends are wrong.
There was a GN 500-car group of cars, GN 75500-75999, with those heap shields, built in 1937 with the same 7-post sides as the Ulrich car, and also the same two-rib flat ends. But the GN cars used a door operating mechanism with chains that wrapped around a shaft, not the Enterprise links modeled on the Ulrich car (you could of course cut off the Ulrich operating-rod parts, and substitute brass wire of scale 1-inch diameter or so). Also, in the early 1950s, GN began to remove and replace those heap shields, so it may depend on your era.
The GN cars were also a little bigger in cubic capacity, due to higher sides, than the Ulrich car, but that is a lesser concern if you only want a model that is "close."