We spotted earlier revealed RM-1038 variant and a new unknown variant RM-1040 at GFXBench. Now, RM-1040 seems to be the global variant as it has already passed certification in Indonesia.
So far we have come to know about three variants of Lumia 730 including the latest one: RM-1038, RM-1039 which most probably belong to US carriers ( may be Single-Sim global as well) and RM-1040 may be the one going globally. Since, it also has a Dual-Sim variant, we expect to see more variants getting revealed in near-future.
