So, if a man who is uncircumcised keeps the precepts of the law, will not his uncircumcision be regarded as circumcision?
Romans 2:26 ESV

If a gentile comes to faith and keeps the commandments, even though he wasn't born as a Jew, he is as a Jew (a praise) in the eyes of God, and God sees him as a party to the covenants. (And the only commandments Paul could have been talking about are those of the Law of Moses.)