Is the Book Gharib al Qur'an fi Shi'r al-'Arab / Masa'il Nafi ibn al-Azraq Trustworthy?

I found this book on shamela through the arabic lexicon website hawramani and it says this is essentially a dictionary of Quranic terminologies explained by Ibn Abbas through Q&A format. But I wanted to be sure if this Book can really be authentically traced to Nafi Ibn al Azraq / Ibn Abbas before I use it. One thing that gave made me doubtful is the version of the book on shamela speaks about Nafi ibn al azraq ( who is supposed to be the Author) in the third person :/ Is this Book authentic?