What do you see as the main similarities? I don't really feel like the Beasties' early rock sounds were that much closer to RATM than, say, Run-DMC or even Schoolly D's "Signifying Rapper". The Anthrax collaboration version of "Bring The Noise" might be even closer, but it was released after RATM's debut was recorded.
Beastie Boys was a hardcore band before all the songs you mentioned, the fourth member is the drummer of Luscious Jackson. Or before they became a rap group.
Edit: Beastie Boys as a hardcore band pre-dates RATM's or Zach's Inside Out. I think the GP is correct.
