On Reddit a user posted a link towards imgur, displaying all the specs from the Radeon 300 Series lineup (excluding Fiji) from MSI.
When you check reddit you'll notice that the information posted on imguru was found & leaked in Brazil by a website called tecmundo, the slides cover the full specs from the MSI R7 370 up-to the R9 390X. All earlier leaked information on the respin products including changed codenames are correct, listed are:
Meanwhile on YouTube; people doing a hands-on unpacking the Radeon R9 390X Graphics cards (Respin R9 290X with 8GB), which they have been able to purchase in stores.
BTW - funniest thing ever is that he calls a backplate a heatsink and then "The Crossfire board can't be Crossfired" as he can't find a Crossfire connector".
Alleged MSI Radeon 300 Series Spec Leak Onto the WWW