Even with the sources available, it doesnt necessarily mean its free. I remember cases in which the sources were open but the license did not allow you to change the code or propagate the program in any way, changed or unchanged. So it could even be "open source" but have licensing issues. (This is, btw, one of the reasons I dont like the term "open source" any more. Experience told me that Richard Stallman was right after all: it is better to call it "free software".)
Anyway, its much too early to speculate now. Lets see what they come up with (and lets wait for the price ). At least one thing they did not do, apparently, is starting some kind of developers program, or did they? I would have expected such a project to try and get some community support before launch...