Hmm, this project doesn't seem to be stemming from Microsoft Zenimax Bethesda Game Studios... there may be trademark and/or copyright issues here... I dunno, something about this gives me bad vibes. Maybe it's just 'cause it ain't OSS.
Anyway Bethesda is really good about this type of thing, they give away some of their of old stuff (Arena and Daggerfall) for free-as-in-beer and considering their cooperation with modders for nearly every title they release I don't think I've ever seen them get ornery over a remake.
Sfall has been around a long time too. I wouldn't worry.
Interplay also did a Fallout classics retail release which included Fallout, Fallout 2, and Fallout Tactics. But Bethesda told them they no longer had the rights and Interplay had to get it pulled off store shelves. This was also around 2009 or thereabouts.