It says a man is justified by faith APART FROM WORKS OF THE LAW. Since the issues in the context were faith and works, the Apostle Paul himself, not merely Luther, is saying that justification is by faith ALONE, i.e., APART FROM WORKS OF THE LAW.
So, Luther's ALONE idea is the idea of the Apostle's text. Luther apparently put the word "alone" in his German-language translation because he was irked at Rome for continually missing the point of the verse.
The word "alone" does not appear in the Greek text (and I don't even care about the Latin text), but the "alone" idea is certainly there.
And as I said in my post, John Calvin's famous explanation of justification is right on target. It readily explains the verse you cited from the Epistle of James. However, the Romanist doctrine of faith-plus-works doesn't have any way of explaining Romans 3:28!
And this is the bottom-line reason why consistent Protestants reject ECT.
Don't be coy. Luther changed Scripture to fit his doctrine, not to clarify St. Paul's writing. St. Paul is clearly teaching that works of the Old Testament Mosaic Law, like circumcision for instance, could not bring about salvation. Faith does bring about salvation, provided it is accompanied by charity. The New Testament makes this clear, despite Luther's editing, in Galatians, 1 Corinthians, John, Matthew, James and Ephesians.
These are just some examples of Scripture that refute Luther along with his own words: "We are obliged to yield many things to the Papists - that they possess the Word of God which we received from them, otherwise we should have known nothing at all about it." Commentary on St. John, Chapter 16.