Section 463 doesn't make a difference between how long ago the election took place. The whole purpose of the legislation is to ensure that there be accurate returns. It's all about transparency and accountability for the expenditures and the transactions that occur during a campaign.
From time to time, information may require that returns be amended to accurately reflect what happens during that campaign. Section 463 doesn't make a difference. Otherwise, you're turning it upside down. It's not because the election is gone that there's no longer a duty to account for that election.