Yep. In the "Grissom scene", The Joker emerges from the shadows, in full makeup, and delivers a line which establishes what we can expect from the rest of his character's screentime,
"You can call me, "Joker"- and as you can see...I'm a lot happier...Ha ha ha ha".
In the "bank robbery scene", The Joker emerges from behind his mask, in full makeup, and delivers a line which establishes what we can expect from the rest of his character's screentime,
"whatever doesn't kill you, makes you...stranger".
I would almost go so far as to say that the mob conference scene is slightly anti-climatic after this, because The Joker appears as a much more hesitant, more vulnerable individual than in his first scene. His later development more than counterbalances this but, again, it amounts to a more gradual introduction to the character than the single iconic moment in B89.