These cars were originally manufactured in Chicago. I'm not sure if production was ever relocated to China or if they were discontinued before Con-Cor relocated most of their manufacturing there.
I'm told that the prototype for this model is likely a Union Pacific BF-70-11 "grainloading" box car. Originally 40' in length, the UP rebuilt them into 50' cars at some point during the 1970's. Consequently, their operational life would've been pretty short since the practice of using box cars to haul grain pretty much came to an end by the early 1980's (with covered hoppers taking over those duties almost exclusively thereafter).