As the mint frequently used to let employees obtain early releases you have no standing to make the assumption it was stolen. In case you haven’t noticed, the burden of proof here is supposed to be on the prosecution...
This is not a criminal case. The government needs to show that the coins were never released and then the burden would shift to the person possessing the item to prove it was a gift and that the person who gave the gift had the authority to do so.
I believe Mr. Lawrence is not going to be able to meet that burden because he stated he does not know how his father came into possession of it.
Once the government establishes that those pennies were ordered destroyed, the burden will shift to Mr. Lawrence to show that the penny he has in his possession was not one of those ordered destroyed. He has already admitted he can't prove that.