Realize that since I've advanced only to the upper 80s/lower 90s pages of this thread, anything I post risks being a repeat…
What interests me about the Grant Building (glad to know the name) is a bit of advertising in the trim above the first floor:
I see "NATURAL FOO…". Given my best Wheel of Fortune skills and the available space for the remainder of the word, my guess would be "NATURAL FOOD". By itself it's a curiosity, but combine that with the country's first vegetarian cafeteria at 3rd and Hill, and it makes me wonder if L.A. was already a hotbed of foodie and granola types a hundred years ago.