Salam. Followers of Ahmad al-Hassan (l.a.) claim, that the book of Sheikh al-Saduq (ra) contains the statement "from Yemen" only inside the brackets. The truth is, that there are two different hadith in the book "Kamal al-din wa-tamam al-ni'mah" which mention "Yamani" and only one of the narrations contain "from Yemen" inside the brackets, the other one is clear. Read here: http://shia-rafidah.com/articles/81-brackets-from-yemen.html#.VFDuBfmG98E There are also multiple authentic hadith, which mention, ''and the emergence of al-Yamani from Yemen with the white flags'' You can read them here: http://shia-rafidah.com/tags/Yamani+from+Yemen/#.VFDuv_mG98E And the great Shia scholar in the field of hadith; Muhaddith al-Nūrī at-Ṭabarsī has mentioned in his book; ''Nafas al-Raḥmān fī faḍāʼil Salmān'', that Yamani is from Yemen. Read here: http://shia-rafidah.com/articles/78-hadith-from-yemen.html#.VFDvvfmG98E