It wouldn't surprise me if this goes away. I find it hard to believe that in 24 hours or less they managed to make this happen correctly and legally.
a) A source code on the web can't just go away.
b) Why shouldn't it be legal? It probably didn't take more than a phone call for Raven to get a green light from Activision (if that was even necessary - maybe they were already allowed to do so all along and just hadn't until now)
For instance, what was stopping them before? Was it LucasArts? Even though LucasArts is gone, Disney still maintains the rights to all their property and the situation wouldn't have changed much.
Maybe nothing was stopping them? Maybe they just didn't think of it/weren't in the mood, maybe they wanted to keep some of their technology safe in case they would create another Star Wars action game someday, who knows...