Getting back to what and how things work, I must point out that "off the rack" wasn't going to work for me with said Mossberg (actually New Haven AT 600, an even cheaper model, if that's possible) gun. It had a blunderbuss like protusion of an adjustable choke on it from the factory, and a plastic safety slide that hurt my little thumb. A Mossberg should have a recoil pad, if it is a 12, also, if you are interested in shooting comfort. A Wolf Creek powdered metal safety, a fixed modified choke 28" ribbed barrel, sling swivels, and a no-nonsense black Pachmayer pad later, it is "fitted". 'Sorta.
I think it could be repeatably duplicated, but, then again, you get into those nuance issues like wood weight-wood, even cheap wood, will weigh differently from piece to piece.
Besides, once is truly enough with one of these....
Best,
Ted