In Davenport I found a pump for $150 that was camo and had an extra choke.  However they don't guarantee it will work and the guy knew about as much as I did regarding whether or not the choke would work and how you put it on.

Normally I'd just buy a new gun but this isn't for any fun or purpose but to shoot pests.  It's just one of those expense things like herbicide I guess. 

Of course if I was buying a new gun I'd probably research it for months before spending any money.  That's half the fun.