The Tel Moza Excavation is one of the most talked about archaeological digs in Israel today. This is largely due to the fact that the team unearthed a temple—complete with walls, a holy of holies, an altar, a cult stand, and figurines/idols—all together in a site about 5 miles west of where the temple of Solomon in Jerusalem once stood.
This article from Bible & Archaeology has a video interview with the Director of the Tel Moza excavation, Shua Kisilevitz
We know that the Israelites were not truly monotheistic until their return from the Babylon Captivity. Even in Solomon’s temple other deities were worshipped. No wonder the prophets went ballistic!
Individual Israelites may have been more or less monotheistic at any point in their history, but the culture as a whole was often not monotheistic until after the exile. The terminology is important to distinguish between the unjustified claim that the ancient Israelites could not have believed in monotheism before a particular time (why not? they were just as capable of thinking or not thinking that as anyone else) and the quite justified assertion that various forms of idolatry were widespread until the impact of the exile. As a complication, idols could have been claimed to represent YHWH, and are technically not proof of non-monotheism, though they would prove non-orthodoxy. Usually multiple deities are represented, though, so I would not be surprised if this example does indicate that some individuals were polytheistic.