The only way you’ll ever know is if you get to Heaven yourself. And at that point, I doubt you’d care.
My friend if you read the post it is not saying if he is or if he is not... it is a challenge for you to consider if you are or not based on the Word of God...
We all are guilty and that is why we need a Savior? A true Christian is one who has judged themselves and has testified to the entire world that I am guilty and need Almighty God’s Savior to save my soul. (Rom. 3:23, 10:2-4, 1 John 4:10).
He has made his decision and I have made mine (John 1:12, Acts 16:28-31). Have you made yours? That is the personal challenge to every one of this post!