I can't guarantee any moving part design will work. I found on this 1/400 model the moving parts don't work because the wax support isn't fully removed by Shapeways. These joint pins are often only 1mm so the wax is stronger than the plastic. So consider all models static with only a chance to have moving parts.
At the larger 1/200 it might allow the back to pivot up like a real dumptruck. It is a captured hinge so do not try to separate the parts or it will break.