It most definitely is, they're going to deprecate the older design over time. Just look at the specs, CPU and GPU are the same between old-style and Retina, but only the Retina gets a 16GB RAM option (with 8 base, versus 4 base for old-style), a retina display, Retina gets HDMI (and a second TB, which is the future as far as Apple's concerned), an updated Magsafe design.

The old-style remains to clear inventory and to wait for the cost of making/buying retina panes to get lower.