The university said Wednesday that it has contacted the NCAA and SEC in order to "rectify" the situation.
"Initial information suggested bills that were exchanged were novelty bills," a statement obtained by Sports Illustrated's Ross Dellenger said. "Information and footage reviewed since shows apparent cash may have also been given to LSU student-athletes."
Beckham was one of several former Tigers who attended the game, which saw LSU overcome defending champion Clemson to capture its fourth national title in program history.
The Cleveland Browns star was seen putting cash in players' hands on the field after the game and then joined the team in the locker room to continue the celebration.
While LSU initially claimed the bills were fake, quarterback Joe Burrow suggested earlier Wednesday that they were real.
"I'm not a student-athlete anymore, so I can say yeah," the graduating senior told Barstool Sports on the "Pardon My Take" podcast.
If the money was real, LSU players could be in violation of amateurism rules.