The biographical sketch of Rabbi Moshe Feinstein that appears in the beginning of Igrot Moshe volume 8 states that his father, Rabbi Dovid Feinstein of Uzda, was born and raised Hassidic, but took on his in-law's very non-Hassidic customs when he married.
So I'll ask: I assume that he started off with Tefilin that use the Hassidically-favored Ktav Ari script. Upon marrying, did he switch to the standard-Ashkenazic Ktav Beit Yosef script? And what about his sons/grandsons? Were they given Ktav Ari tefilin?