well, it really depends whom you consider “hamon am”, most of the hamon am I’m surrounded by, the majority is makpid for Magen Avraham l’chatchila, only some would rely on the Gr”a.
BTW, the Chabadnik’s are also relying on that second zeman, cuz the Shulchan aruch harav (Tanya) also accepted that zeman.