We just reported the size specs of first Dual-Sim Lumia, the Lumia 630 via a leaked product data sheet image. Now, the device has passed certification at FCC and if you will see the size specs revealed in its SAR report, it matches digit to digit to the specs revealed in PDS.
If you remember RM-977 has appeared in both Single-Sim and Dual-Sim avatars in Zauba records. So, possibly in some markets this 3G device will be launched as a Single-Sim while in other markets as Dual-Sim device.
This may explain why the below Lumia 630 image posted by evleaks shows a single-sim device, while the product data sheet image above and screenshot posted before has Lumia 630 as Dual-Sim device.
So, we may be looking at 3 devices,