Looks like two different trucks now in this discussion, a 1940 and a 1960.
They each have 10 lug on 7.25" bolt circle.
The earlier truck has 4.75" (or smaller?) center bore.
The later has 5.25" center bore.
The change to larger center bore was about 1955-1956.
Later wheels work on earlier hubs with a bushing to take up the difference.
Earlier wheels could fit later trucks after boring out the center bore to suit, as Mike explained.
