Justification and Time Table

In his recent small book, Wright says (Justification 122),

“It is vital to distinguish two things: the status of God’s people, prior to anything they do, and the life they are called to lead, which points forward to the eventual judgment.”

“The works in question will not earn their performers their membership within God’s true, eschatological, covenant people; they will demonstrate that membership.” (124)

For Wright, justification by faith is a matter of “how can  you tell you are already in the people of covenant.” When we  paraphrase Paul's passage in Galatians (2:16), however, this interpretation is hard to make sense: 

“We can tell whether a given human being is already in the  people of God not by the Jewish badge but by faith.” 

This is a post-event description, and well keeps the aspect of  grace. Yet, if both faith and works of the law are merely  sign-post, it cannot explain Paul’s vehement denial. How  can such a sign-post AND the response in gratitude nullify  God’s grace?

I was surprized to find that, despite the extensive research  on "works of the law" by Dunn and other "New Perspective"  scholars, a convincing interpretation of the meaning  of "being justifed" still lacks (especially in terms of time- frame (present or future)?)! Also Sanders's category  of "getting in" and "staying in" doesn't seem to work well  in discussing "being righteous". What was at stake in Gal 2- 3? For Hays and Sanders (and sometimes Dunn), it’s  about “getting in.” But this understanding contradicts to  their interpretation of the covenantal nomism. “Getting in”  is always by the initiative act of God, hence no need of  argumentation (neither about faith nor works of the law)!  Let us paraphrase Gal 2:16 using their interpretation:  “knowing that a human being is not getting in to the  covenant membership (or the family of Abraham) by “Jewish  identity marker” except through faith of/in Jesus the  Messiah.” According to the covenantal nomism, works are  always the man’s response to God’s gracious act. That  is, “getting in” precedes Jewish identity marker, hence  logically the paraphrase above doesn’t make sense. 

 Maybe this question is due to my incomplete grasp of current  research.