If the shotgun you pick up at the show is a fixed choke, then you can get a poly choke. That is a choke that mounts to the outside of the barrel and allows you to choose the amount of restriction by twisting it. They are not all that popular because they can affect patterning.
If you are hunting turkeys, the best choke is an aftermarket turkey choke. Next best is your standard full choke tube. For trap i like to go with a modified, or improved modified.
Hope this helps, happy hunting