that's a good guess. They already said she was Black Canary, though. And Lady Shiva already showed up (she was Ollie's cop girlfriend from season one using
But you know what.... the beauty of this show is that as a comic book fan... I have no idea what they could or may be doing with characters, have been pleasantly suprised when I've been wrong and it has all been perfectly fine!!!!
I had the same feeling when they reveal the real deathstroke...