Yes, that could be, Russ, but the D&RGW wouldn't have ordered them if it didn't need them. Conversely the C&S probably would not have let them go if it needed them for its own customers.
According to the traffic patterns that I have read about on the C&S, the stock cars were used to move Texas cattle to their summer range in South Park, after a transfer from the Broad Gauge. There is an ICC case covering a rate dispute over moving the cattle north.
Rick