Those would be my first two guesses as well. But, I think it might be possible that it could have been a passing reference in a few others although I don't recall such a reference. Treasure Mountain might be a possibility because part of it takes place in the New Orleans area. Rivers West and Ride the River might be longshots. And, Lando might be another longshot. Might have been some possible references in non-Sackett stories like Matagorda or The First Fast Draw. Of these two, I would look at the TFFD first because it takes place in Louisiana. But, speaking honestly, I don't recall this reference.