...these two wheels are quite different, indeed. The different resins used to improve the braking surface, alone, are enough to classify the wheel as VERY different, especially if you are taking about clinchers. Recall that several other carbon clincher manufacturers (Enve, Easton and I think Zipp too )changed up their clincher design for model year 2011 (with a specific focus on braking surface) resulting in an increase in rim weights across all manufacturers. In addition to the braking surface and swirl lip on the Reynolds they also went to full Aerolite spokes on rear wheel.
The changes in the wheel design and the many documented issues of heat build up and wheel failure on pre-2011 rims (i.e. DV46) is sufficient reason to steer clear of the older rims.
Here is a link to a previous discussion:viewtopic.php?f=3&t=82499&hilit=+reynolds