Thanks to the online posting of the Unionville Republican (August 7, 1918 issue), I was able to find that my grandfather (along with 14 other young men) were entrained to Jefferson Barracks.
The 15 were; George W. Arnold, John J. Freeborn, R. F. Scalf, Clio E. Dixon, John R. Baldock, Ross Humphreys, Howard Keller, Thomas R. Probasco, Wilber K. Davis, James C. Atkins, Claude A. Brewer, Luther Montgomery, Francis M. Perkins, Glen McNabb, & Verl E. Guffey.
Previous weeks issues & following weeks issues also list other men.
My grandfather Dixon was designated as a replacement -- as I imagine all these men were this late into the war, and thus would serve in all different divisions & units.
From Jefferson Barracks, my grandpa was transferred to Camp MacArthur. He wound up in the 41st Division, 162nd Infantry, Company C and spent 4 months in France. He was discharged from Camp Funston January 30, 1919.
Family members of the above listed men wanting to obtain military information about their relative, I would strongly recommend the MO State Archives. From them I obtained his induction form, his service record, and a copy of his final pay voucher. Most of the National WW1 military records were destroyed by fire in 1973 at the St. Louis record center.