Yes, notice the word also. It means in addition to. In other words they were added in afterward. That's what he explains in chapter 2. I'm not sure why you're rejecting the grammar. He states unequivocally that the "you" group is the Gentiles in chapter 2.
11 Therefore remember that you, once Gentiles in the flesh-- who are called Uncircumcision by what is called the Circumcision made in the flesh by hands--
12 that at that time you were without Christ, being aliens from the commonwealth of Israel and strangers from the covenants of promise, having no hope and without God in the world. (Eph. 2:11-12 NKJ)
Even apart from the grammar, he plainly states, "you, once Gentiles in the flesh". The Jews weren't Gentiles in the flesh, the Gentiles were. Paul included himself in he "we" group. The "we" group is not the Gentiles, therefore it must be the Jews as the contrast is Jew and Gentile. In addition, those things stated in 1-3:12 are all things that pertain to the Jews. This couldn't really be more clear. We just need to read it in context and not grab a verse here and there and apply it to a preconceived idea.