Yes, it is official now!! In all the regions except North America, Lumia 1320 is receiving Lumia Cyan now. We checked the tracker for all the regions and we can see Lumia Cyan update for Lumia 1320 update marked as available across many markets now.
You may like to read some of earlier posts for any help required with update,
[Running Developers preview & BitLocker encryption, need a software rollback before updating to Lumia Cyan]
[Just updated to Windows Phone 8.1 (Lumia Cyan)? Here is your guide to Niravana!!]
For catching everything about Lumia Cyan and Windows Phone 8.1 which includes:- Full Changelog, Hands-on demo videos, Tips, Tutorial no better place than our dedicated Lumia Cyan and Windows Phone 8.1 page.