I agree with @cinnamon1212. I was also a partner at BigLaw and very involved with hiring. I linked an interesting article on this thread about where Supreme Court clerks attended undergrad. More relevant, the article also cited where Harvard law school students went undergrad . NYT Article on Supreme Court Clerkships and Undergrad College (NYT article gifted within that thread).
From the article:
"The study, which considered 22,475 Harvard Law graduates, took account of three data points: where they went to college, whether they qualified for academic honors in law school (graduating cum laude, magna cum laude or summa cum laude) and whether they obtained a Supreme Court clerkship.
About half of the graduates had attended one of 22 selective undergraduate institutions, and more than a fifth of the graduates had gone to college at Harvard, Yale or Princeton."
Sure Harvard law grads come from all varieties of schools, but the top 22, and especially HYP, over indexed beyond what you can account for if only GPA and LSAT scores were considered.