First a word of caution!! This may entirely end as speculation.
We know Verizon Bound Lumia 1320 aka Lumia 929 has passed the FCC as RM-927.
Now, this device which is supposed to pack next-gen specs like Quadcore Snapdragon 800, 1080p resolution and 20 MP PureView camera may have a screen size of 5-inch compared to monstrous 6-inch of Lumia 1520.
While Lumia 1520’s variants RM-940 for AT&T, RM-937 and RM-938 have already passed through FCC, but many would love to have Lumia 1320 with more practical 5-inch size as their next Lumia flagship phone. So, having a look at the below screnshot which shows Nokia phones compatible with latest Nokia Care Suite 5.0 2013.38.3.2 gives us variants like RM-928 and RM-929 which considering the Lumia device variants naming may well be variants of the same device.
If you remember, we revealed variants of Lumia 1520 like RM-938, RM-939, RM-940 etc from similar list,
So, while there may be a good possibility of RM-928 and RM-929 coming true as Lumia 1320 variants, let us wait for more appearances before confirming it.
As Narendra’s findings confirm, these two RM-928 and RM-929 are not Lumia 1320 variants. But it would be really great, if Nokia brings it globally!!