Interesting! I saw the Carole King musical and I can't remember if thye namecheck the location of the office where they are writing, but you are right, I would have incorrectly assumed it was the Brill building!

My favorite mention of it in song is in the Magnetic Fields' "Epitaph for my Heart" :

Who will mourn the passing of my heart?

Will its little droppings climb the pop chart?

Who'll take its ashes and singing, fling

Them from the top of the Brill Building?

But maybe Stephin Merritt should have done more research! 😉