O S and Sarah: well, after doing a bit of research, both the American Scale Models' Andrews truck AND the Rich Yoder' Andrews are correct. The ASM for the CB&Q SM-16 stock cars and the RY for the CB&Q SM-18 cars. My sources: Burlington Route Historical Society Bulletin No.25, "Stock Cars and Livestock Traffic" (unfortunately now out of print, but the definitive resource) and the excellent drawings by Bob Hundman of the SM-18 car, in the "Mainline Modeler" June 1991 issue (reproduced by OS, above).
The SM-16's were built initially by American Car & Foundry in 1922 with a 60,000 lb capacity. A second batch was delivered in 1924, constructed by Streator Car works, of Streator, IL (a new one on me !)
The CB&Q Aurora (IL) Shops built 500 SM-18's in 1926, nearly identical to the SM-16's, except with the use of a heavier duty Andrews truck, the capacity was increased to 80,000 lbs. This truck is identical to the Rich Yoder' Andrews.
So, everybody dances !!