Is this is the first time ever two teams with losing records are in a playoff relevant game on the last day of the season?
In 2010, the Seahawks and Rams were basically in this position. Rams were 7-8 facing the Seahawks at 6-9. Winner of that game wins the division (Seahawks would win it by achieving the tiebreaker over the Rams.)
And in 2014, Carolina was 6-8-1 facing Atlanta at 6-9. New Orleans was also 6-9, facing the 2-13 Tampa Bay. One of those three 6-win teams was going to win that division.