Benchlife.info, via WCCFTech, believes that AMD's Radeon R9 300-series GPUs will launch in late June. Specifically, the R9 380, the R7 370, and the R7 360 will arrive on the 18th of June. These are listed as OEM parts, as we have mentioned on the podcast, which Ryan speculates could mean that the flagship Fiji XT might go by a different name. Benchlife.info seems to think that it will be called by the R9 390(X) though, and that it will be released on the 24th of June.
WCCFTech is a bit more timid, calling it simply “Fiji XT”.
In relation to industry events, this has the OEM lineup launching on the last day of E3 and Fiji XT launching in the middle of the following week. This feels a little weird, especially because AMD's E3 event with PC Gamer is on the 16th. While it makes sense for AMD to announce the launch a few days before it happens, that doesn't make sense for OEM parts unless they were going to announce a line of pre-built PCs. The most likely candidate to launch gaming PCs is Valve, and they're one of the few companies that are absent from AMD's event.
And this is where I run out of ideas. Launching a line of OEM parts at E3 is weird unless it was to open the flood gates for OEMs to make their own announcements. Unless Valve is scheduled to make an announcement earlier in the day, or a surprise appearance at the event, that seems unlikely. Something seems up, though.