Let me ask the question this way: Do you see anything in the article or the photograph that indicate that the carvings are based on Christianity rather than some other culture that had the stories of the Old Testament, such as the Jews.
No, I'm making the broader point that it may not require a museum sign with a pointing arrow in order to possibly be understood.
>If there is no mention of Jesus on these stones, how does he know the designs are Christian? They could be Jewish.
I really haven't had a chance to examine the stones under laboratory conditions (nor have you) so cannot give the definitive answer you apparently and argumentatively seek. (You have to be loads of fun to be around.) Furthur, I am not qualified to make definitive judgements (nor are you) about what is or is not a Christian symbol of that time.
In that absence, I will either (1) accept theology professor Wang Weifans premise, based on his presumed authority, that some stone engravings demonstrate Bible stories and designs of early Christian times: or (2) assume a default position that they may be Old Testament stories of the Israelites, either Northern Kingdom or Southern Kingdom.