I read that they cost about $15,000 in 1937. That is roughly equivalent to $240,000 today. Seems about right.
I have been searching online to see if I can determine what happened to these five truck and trailer rigs but I am not finding anything later than all the press about the expedition.
Did they get left in Africa? Were they shipped back to the states (he retired to Wisconsin I think). Were they scrapped? Are any of them still around?