I'd politely decline and get a gun that meets your needs from the get go. Whatever you save on the gun initially, you will spend making the gun the way you really want it. Frankly, with all the horror stories I've heard (and seen) with the Mossberg, I'd recommend you either save some $$$ and buy a used Remington 11-87 (~$400), or spend a little extra and get a new Versa Max Sportsman (~$750).