No,but I understand his doubt because we don't have full sets of the supposed original. I accept these things on FAITH because I trust the Church.
I am reminded of the incident in scripture in which Josiah commanded the temple to be refurbished. There in a hidden room, they found the word of God after 400 years in which it was missing. Josiah read from that holy text to the people from sun up to sun down while all the people stood the entire day listening to it.
People did not call into question the authenticity of the text that had been missing for 400 years. Nor did they figure that it was the word of God simply because Josiah said it was and they took it on faith in Josiah. And, one would suppose that after 400 years it was probably a bit tatter and parts were missing. That didn't seem to matter. They knew that it was the word of God because God speaks to His people through the words and His people hear His voice. And when they heard the word read by Josiah, the people wept.
We know that the scriptures are the word of God because God speaks to us through them. Not because we can prove their authentication, or we take it on faith from someone, or that we accept portions that we like. If a person cannot hear God through His holy word, he should ask himself as to why not.