raisitup,
With the Mossberg's safety location, using a AR-style stock (or any thumb hole style stock) makes operating the safety awkward at best -- stay with a standard stock on a Mossy.
If you mean a pistol grip only (PGO) stock, then go for it -- if you're like most folks, after some serious trigger time, you'll change back to the conventional stock a wiser man.
If you really want an AR-style stock, then get a Remington with the safety in the trigger guard.