I actually pulled the citations from here:
https://beggarsallreformation.blogspot.com/2006/02/luther-added-word-alone-to-romans-328.html
Yep. A good one.
Even some Catholic versions of the New Testament also translated Romans 3:28 as did Luther. The Nuremberg Bible (1483), allein durch den glauben and the Italian Bibles of Geneva (1476) and of Venice (1538) say per sola fede.
The poster was wrong indeed!... but so insistent!