As I understand it, the forearm is differant in how it's attached to the rails. It's pinned in place where the Mossy's are fastened differently. You can also swap trigger groups with a Mossy,you just won't have a safety-not a good thing on a weapon you want to walk around the house @ 0300 with.
I had one,loved it. Light,a little rough at first but nothing a few boxes of shells won't fix. I like it so much I sold it and upgraded all the way to a Mossberg 590A1. Now I want a Mav 88 again. The 590A1 is a great shotgun,but for the house I find it a little long and nose heavy.
Not to mention,if you shoot somebody that weapon is going out the door with PD and may be gone for some time-if it EVER comes back. Better to lose a $200 Mav 88 than a $450 590A1.
Sorry,got OT there- I think the Maverick 88 is an excellent choice for HD. Light,easy to use,low cost- very good.