I've read it seems like the 380 will be Tonga chips, and the 390 Hawaii again. A bit underwhelming, specially next to the fake leaked specs from mid 2014, but I guess you can only go so far with 28 nm. Fiji is going to be a high-end brand which will either be called 395, or a whole new series, equivalent of a Nvidia Titan. So, if I were to guess...
R9 380 = Tonga PRO
R9 380X = Tonga XT
R9 390 = Hawaii XT
R9 390X = Hawaii XTX?
R9 new brand = Fiji?