Even sunnis understand that the Hour in the Quran is refered to the Qa’em/Mahdi (as) > Ibn Hajar wrote that: Muqatil Ibn Sulayman and those who followed him among the (Sunni) commentators of Quran said that the verse: “And he shall be a Sign for (the coming of) the Hour” (Quran 43:61) was revealed about al-Mahdi. Sunni reference: al-Sawa’iq al-Muhriqah, by Ibn Hajar, Ch. 11, section 1, p247