Rolling Blackouts have yet to even release their Sub Pop debut – Hope Downs is due out June 15th – but the band already had no trouble packing in a crowd for their first Boston gig. With two EPs of effortless guitar-pop under their belt, they’re riding a justified wave of buzz. And it should only be bolstered further by a tight, propulsive live set like Friday night’s. They had charm and hooks to spare, they previewed new songs that sounded even better than the old ones, and a small, sweaty rock club felt like the perfect place to see them do it. Just don’t expect that opportunity to be around much longer – bigger stages than Great Scott are definitely on their horizon.