I went Thursday before last with other archeology students and one of the BIU archeology professors, Prof. Aren Maeir, to Tel Lachish. He mentioned there that the Motza temple is most likely evidence for the religious reform of Chizkiyahu's time and not Yoshiyahu's (this is probably based on the dating of the layers and various finds). Evidence for Chizkiyahu's reform may also be found there in Lachish, where one of the city gates' rooms was excavated and discovered to have held an altar upon which a chamber-pot-stone had been placed. Note: I asked, and this is probably not evidence for a Baal Pe'or cultic site because the chamber-pot-stone was found buried over the cultic objects in the room, not in the same layer. For more info on the discoveries in Lachish, see here.