Does Lawrenceville weight GPAs for their more rigorous classes?
No. And AFAIK, none of the more selective schools weight.
Don’t Choate and Taft weight?
I stand corrected;I guess you found the exceptions.
Actually, I don’t believe Choate really weights their gpa calculations because their college profile says " Choate’s official grade point average (GPA) is an unweighted GPA that is displayed on the transcript. A 4.0 point system is used for the GPA calculation…weighted GPAs appear only on the Secondary School Report." I think that pretty much leaves Taft as the only ‘top’ school that weights their gpa. Overall, I don’t think whether a school’s gpa is weighted or unweighted gpa’s make a difference. Colleges are really looking for students who take the most rigorous course load and succeed while they are doing it. Whether the gpa is weighted or unweighted, they can quickly tell which students have and which students haven’t done this.
https://www.choate.edu/uploaded/Documents/Academics/College_Profile.pdf
Certainly not a reason to choose or reject a school.
Lawrenceville does not weight GPAs. However students who get an A+ in a class get a 4.3. So its theoretically possible to have a higher than 4.0 GPA at the time of graduation.