I have this model also. Only the fifth driver has traction tires; Otherwise it is the same as the first driver
which does not have traction tires. Since he has six of these models, he could swap the first driver from
three locos for the rear driver of the other three.
That would give him three locos with no traction tires and three locos with traction tires on the first and fifth drivers.
He might find another modeler who likes traction tires who might desire the three locos with two drivers with traction tires.
A swap might be in the future.
At the very least he could do the swap with just two engines and compare three variations; As built with one driver with
traction tires, traction tires on the first and last driver, and his intended version, no traction tires.
HO and Sn42