The serial number suggests a 1980 manufacture, but none of my references mention a Mississippi River Gambler / New Orleans commemorative. Even the Winchester Collectors site has nothing. Since it is marked 1 of 40, I would guess that it was custom produced for a special event in New Orleans. It may have been a factory job, or it may have been customized afterwards (I am familiar with a similar production done for the various counties in Pennsylvania). Good luck with your search.
Mississippi River Mississippi River
The Mississippi River is important to the new Orleans because ships need to carry products on it.
New Orleans stands on the Mississippi river.
New Orleans is right by the Mississippi River.
New Orleans is about 90 miles from the mouth of the Mississippi River.