The coin the Accountant uses throughout the movie is an Obolos, from ancient Greece. In those days, Obolos were placed in a dead man's hand (or two over his eyelids) by mourners as payment to Charon the Ferryman, who was in charge of crossing souls over river Styx into Hades, the Greek version of Hell. This would support the Accountant's role as a retriever of lost souls.
When The Accountant is driving the hydrogen truck, the truck is incorrectly labeled with a UN hazardous materials placard bearing the number 1075. 1075 is the UN number for liquid propane, not hydrogen.