I think this thread has progressed enough that we can safely say that all who were saved under the Old Covenant were saved by faith and that their salvation was perfected in the death of Christ. The thief on the cross regardless of the covenant was saved by faith. The reason it doesn't matter is because people are saved on both sides of the death of Christ on the basis of their faith and His work. The Scripture is clear that the path to salvation has always been the same. Faith.
It is clear in Scripture that circumcision was about obedience. Circumcision alone however accomplished nothing. It was faith that was the issue, and people of faith under the Old Covenant were circumcised. People of faith under the New Covenant are baptized. Faith is the issue. Baptism does nothing on its own, it saves no one. Abraham was saved by faith apart from circumcision, but through obedience was circumcised. Believers today are saved through faith and are baptized out of obedience. The Thief is a perfect example, he was neither baptized nor circumcised after belief. Salvation is at faith under both Covenants.
Romans 4:3-13
3For what saith the scripture? Abraham believed God, and it was counted unto him for righteousness.
4Now to him that worketh is the reward not reckoned of grace, but of debt.
5But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness.
6Even as David also describeth the blessedness of the man, unto whom God imputeth righteousness without works,
7Saying, Blessed are they whose iniquities are forgiven, and whose sins are covered.
11And he received the sign of circumcision, a seal of the righteousness of the faith which he had yet being uncircumcised: that he might be the father of all them that believe, though they be not circumcised; that righteousness might be imputed unto them also:
12And the father of circumcision to them who are not of the circumcision only, but who also walk in the steps of that faith of our father Abraham, which he had being yet uncircumcised.
13For the promise, that he should be the heir of the world, was not to Abraham, or to his seed, through the law, but through the righteousness of faith.
8Blessed is the man to whom the Lord will not impute sin.
9Cometh this blessedness then upon the circumcision only, or upon the uncircumcision also? for we say that faith was reckoned to Abraham for righteousness.
10How was it then reckoned? when he was in circumcision, or in uncircumcision? Not in circumcision, but in uncircumcision.