Biden - The Best Communicator in the White House

Biden was asked about classified documents in this interview and he put a timeline on his own classified documents he may have. He referred back to his first year in Congress saying that some documents might date back 4050 years. That's now we're talking about a 50 year window here. I don't understand what Biden was doing. If he was taking classified documents out of the Senate 4050 years ago, maybe they didn't have skiffs back in the days of horses and buggies.