I've never owned a Mossberg, so I can't really say for sure. And I don't want to offend anybody, by bashing them...But if it were me I would keep the Benelli. Just in case.
Besides, if you don't NEED the money, your Benelli will most likey hold value better than the M'berg...you can always sell it later.
**Most every gun that I have sold, I wish I would have kept...it's hard to do good on a gun sale if the model or a new version is still in production. People would just as soon have a new one, for a little more $$