I recently came across the following rendering of chapter 32 of First Clement. This is Maxwell Staniforth's translation, edited by Andrew Louth. Notice that Staniforth expresses Clement of Rome's sentiments by adding the qualifier "alone" to faith:
"Similarly we also, who by His will have been called in Christ Jesus, are not justified by ourselves or our own wisdom or understanding or godliness, nor by such deeds as we have done in holiness of heart, but by that faith through which alone Almighty God has justified all men since the beginning of time." (Early Christian Writings [New York, New York: Penguin Books, 1987], 36)
For my argument that Clement was affirming faith alone in a Protestant sense, see the thread here, including the comments section.