Where does it claim it is an "original"?
Mea culpa!
It states that it "It likely adorned the entrance of a synagogue that was destroyed by the Romans between A.D. 400 and 600, or by the Crusaders in the 11th century,".
I should probably - no, knowing the nit-pickers on here, I SHOULD have said "very early" or "ancient" - whatever appellation you apply to it there is, apparently, no version older!