Larry Hurtado mentioned on his blog that yet another early manuscript of the Septuagint has been found that uses the divine name instead of Lord (kurios), this time representing the divine name with ancient Hebrew letters (YHWH) in what is the earliest extant copy of the Psalms in Greek. Hurtado argues that the use of the definite article before the divine name indicates that the manuscript relies on earlier copies that used Lord (kurios), but the fact remains that all the earliest copies of the Septuagint that have survived use some form of the divine name and none use Lord (kurios) as a substitute. That's about ten out of ten for manuscripts of the Septuagint earlier than mid-second century C.E so far.
http://larryhurtado.wordpress.com/2013/07/02/new-oxyrhynchus-manuscripts/