There are a lot differences, mostly subtle but there are changes over the years. I consider the early ones the most desirable/ valuable- say 1965 - 1969.
It will take a little time for me to start to begin pointing out the differences.
The new "one piece" wheels are all cast aluminum, as seen here:
They don't lok like the old Cragar SS wheels at all. They do share a resemblance to the old GT wheels since the shape seems to resemble the flatter spoke of the original GT and the centers are the unchromed aluminum.
The new wheels look good and stylish, but they are not the real-deal. As much as thye might look good today, they do not have the timeless style than an original wheel of the era. Long term, those wheels will date the car in a negative way.