Yes, they still teach that totally wrong interpretation. The Watch Tower Society began using the expression “world empire of false religion” in 1963 (in “Babylon the Great Has Fallen!”, God’s Kingdom Rules!). Prior to that, it associated “Babylon the Great” with ‘Christendom’, further contradicting the claim that special ‘enlightenment’ was provided to them in 1919.
“Babylon the Great” in Revelation represents ancient Rome, which has been understood for many centuries, and Christians could readily identify “Babylon the Great” as Rome when Revelation was first written. Revelation 17:9 guides the reader to the actual identity of “Babylon the Great”, with its statement that the “seven heads” of the ‘beast’ she rides represent “seven mountains”—the ‘seven hills of Rome’. (Coins minted during the reign of Vespasian depict Roma—a female deity who personified Rome—seated on seven hills.) This would be an obvious clue to 1st-century Christians, who were well aware of Rome as an enemy of Christianity. Additionally, the reference to “disgusting things” at Revelation 17:4 and 5 is reminiscent of the earlier warning to flee Jerusalem before the Roman attack in 70 CE (Matthew 24:15; Mark 13:14).
The Roman Empire oversaw various subordinate client kingdoms, each with its own ‘king’. Judea was itself one such client kingdom, under the jurisdiction of Herod, who is described as a king at Matthew 2:3 and Mark 6:14 using the same Greek term as at Revelation 17:2 (basileus, βασιλεύς, Strong’s G935). Revelation 17:18 accurately describes “Babylon the Great”—that is, ancient Rome—as a city with a kingdom over other kings.
No mystery, no nonsense.