Oh, where to begin a response? So, perhaps some discussion ending questions.
Since the books at the TexasSchoolBookDepository had an ultimate destination to schools, do you, MrStoring, have any estimate about the number of schools in '63, in Texas, that had loading/unloading docks? Do you have any estimate about the number of schools in '63, in Texas, that had Forklifts? And, do you have any estimate about the number of schools in '63, in Texas, that were equipped with elevators when there were two or more floor levels?
It is highly doubtful that books were delivered DIRECTLY from the TSBD to individual schools. I have lived in several states and they All had their own Distribution Center from which school supplies were distributed to each individual school as needed. This distribution was done by Vans or Trucks along the lines of a UPS Brown Truck. Loading docks and elevators physically being part of a school would be a Dangerous Liability.