What Text of Genesis Was Paul Using?

Thirdly, Paul adds “Adam,” so that his version now reads, “the first man Adam became a living being,” where the LXX reads simply, “the man became a living being.” While none of the LXX MSS have the word “Adam,” both Theodotion and and Symmachus have “the Adam man” (the reverse word order to Paul) at this point in their texts.  The Marcionite text of Marcus in the Dialogues of Adamantius read, "the first man Adam became a living being (ἐγένετο ὁ πρῶτος ἄνθρωπος εἰς ψυχὴν ζῶσαν) the last, the Lord, a life-producing spirit. The first man was of the earth, earthly; the second, the Lord was from." The LXX text of Genesis 2:7 reads "καὶ ἔπλασεν ὁ θεὸς τὸν ἄνθρωπον χοῦν ἀπὸ τῆς γῆς καὶ ἐνεφύσησεν εἰς τὸ πρόσωπον αὐτοῦ πνοὴν ζωῆς, καὶ ἐγένετο ὁ ἄνθρωπος εἰς ψυχὴν ζῶσαν."  The Samaritikon?