Vicki Po says she carbon dated the metal fibers from the wound; they were a tin and copper alloy (probably bronze) forged between 10 and 70 A.D. While iron was becoming common in the Roman area at this time, and there was even steel made in small batches, bronze was still much more affordable. However, you can only carbon date organic matter by looking at its C14 content. There is no comparable way to date metals.