unfortunately it looks like it is.
As I understand it, the Android devices that support dual voice and data are 1) SVDO capable, and 2) have 2 antennas -- one for CDMA/EVDO, one for LTE.
LTE does not support voice at all, so the way it works is, when your data is pulled down via LTE, you can still use voice over the CDMA/EVDO antenna.
When you're not in an LTE coverage area, SVDO enables simultaneous voice and data. (One of the iPhone 5 videos says that it supports SVDO, but the announcements haven't mentioned that it's still capable of the dual voice/data.)
In any event, Apple put the LTE and CDMA/EVDO together on one antenna, to save space, weight, and battery. As a result, there can't be dual voice/data while connected to LTE -- at least, not until LTE supports voice, which it will some day.
The real question will be, since the 5 allegedly supports SVDO, is whether you can get dual voice/data over 3G/EVDO.
Guess we'll see.