Yes, he is!
Remember when the Apostles tried to replace Judas Iscariot by giving Elohim two choices to pick from? Well, how did that work out for them? Jesus chose Saul of Tarsus, and we never heard about Matthias again.
Likewise, I believe we have never been without a True Pope, even if Elohim had to pick and name him Himself.
**Remember when the Apostles tried to replace Judas Iscariot by giving Elohim two choices to pick from? Well, how did that work out for them? Jesus chose Saul of Tarsus, and we never heard about Matthias again.**
Tried to replace? They did replace Judas, as David prophesied that they would. And they did so with a man that had been one of the followers (but not one of the twelve), “...all the time that the Lord Jesus went in and out among us. Beginning from the baptism of John, unto that same day that he was taken up from us, must one be ordained to be a witness with us of his resurrection”. Acts 1:1,22
As far as there not being any scripture about Matthias after his being chosen, it seems that over half of the eleven are not written about after Acts 1:13. We do see that “...by the hands of the apostles were many signs and wonders wrought among the people...”. Acts 5:12.
With your seemingly certain opinion of Mattias, are you sure that he was not among the apostles as they performed the signs and wonders?