Okay,
Finally following up on the differences in these two wheels.
I had the tires stripped off the late wheels and now we can see the "internal" differences between the early and late wheels.
Here are the two side by side from the front. At first glance, they don't seem much different. As I stated above, they're somewhat different. This picture doesn't really show it, but the later wheel, (left) has a brighter anodizing finish. The early wheel's (right) anodizing is sorta pale compared to the ceramic coated appearance of the later wheel.
Some more side by side pictures. Late is on left, early on right:
As you can see below, the late wheel (left) is painted black within the rims, the early wheel (right) is unpainted.
In this next picture, you can see the difference in the interior of the wheels. The faces of the wheels are on the bottom of the picture in my hand. The early (left) wheel doesn't seem to have as prominent of a bead seat as the later wheel. Since the finishes are different colors, this looks even more apparent. You can feel the higher ridges on the black late wheel. The ridges feel smoother on the later wheel.
This picture also shows how the taper of the back barrels (angled middle part of wheel) of the wheels are different. The late wheel has a sharper taper towards the hub of the wheel. The early wheel is not as steep.
This shows the rear of the two wheels from the outside. The early is on the left and the late is on the right.
Basically, after all of this mumbo jumbo, it seems to me that the later wheel is the heavier-duty of the two. Which would make sense. As the 911 got a little heavier after 1983, maybe the smart Germans decided to make the front wheels a little beefier???? I dunno, but that's my theory anyway.