That's totally false. The Apostles wrote God's name as Κύριος (Lord) and as Κύριος ὁ θεὸς (The Lord God) on the NT. The Vulgate was written at least 4 centuries after the Greek Koine NT text.
And even before the NT, it was the Alexandrian Jews who decided to replace all occurrences of YHWH with the word Lord "κύριος", when they created the Koine Greek OT (LXX) in the 3rd century BC.
Exodus 3:15) (Brenton) And God said again to Moses, Thus shalt thou say to the sons of Israel, The Lord God (Κύριος ὁ θεὸς) of our fathers, the God of Abraam, and God of Isaac, and God of Jacob, has sent me to you: this is my name for ever, and my memorial to generations of generations.
Notice the "Lord God" (Κύριος ὁ θεὸς) portion of God's name. The phrase Κύριος ὁ θεὸς is from the Alexandrian Septuagint (LXX) OT text, the same text that the Apostles overwhelmingly quoted from to formulate the NT.