Probably. A lot of things that have been copyrighted were required to have a copy sent to the copyright office and, by extension, the library of congress. At least in the past

https://www.reuters.com/legal/litigation/us-appeals-court-curbs-copyright-offices-mandatory-deposit-policy-2023-08-29/

In a ruling, opens new tab for Richmond, Virginia-based Valancourt Books, the U.S. Court of Appeals for the District of Columbia Circuit said the Copyright Office's demand amounted to an unconstitutional government taking of Valancourt's property.

The applicable portion related to these older works here

The Copyright Office requires a physical copy of any work published in the United States to be deposited with it. The office has said the requirement ensures that the Library of Congress "has an opportunity to obtain copies of every copyrightable work published in the United States"

If the website ever filed for copyrights then the site contents itself may fall under the same purview.