Legacy question

We have had three generations (including my own) go to American University - two grad school and one undergrad. The most direct legacy to my child would be her great-grandmother (my maternal grandmother) who received a Masters in International Affairs in 1939 from AU and continued taking classes there until she was in her 80s! On the common App, American asks if you have a parent or grandparent who is a former AU graduate. Is it safe to assume a great-grandparent is not something to mention? I think a woman receiving a masters degree in the 1930s is a very interesting legacy, but I’m guessing they don’t care about anyone beyond a first degree grandparent. Does it even matter if she is applying regular decision? Thanks.