It seems quite hard, to my eyes, to relate any of the pictures, model or 1:1 version, to each other.
The 1:1 GN car has a larger capacity than the USAT model and its sides are slab whereas the model has a taper at the top part of the car. The 1.32 MDC, whilst spartan, does seem to resemble the prototype somewhat in body shape more than the USAT one.
I did wonder if they are, in fact, the same thing: is the Colorado USAT model that of a special specification for a mineral line whereas the GN a slightly larger bodied version for a Class 1 railroad. I will be interested in the outcome of this enquiry.