i dont know the answers to your questions, but i have one of these. got it at my local gunshop for around 300$ NIB. he still has a few left.
This was my first shotgun ever, and its GREAT. its a dream to shoulder, recoil feels less then my AK (the large rubber buttpad works great) the trigger is PERFECT for a shotgun, action was ultra smooth out the box, and i love the OD finish.
as for durability of the finish, im not sure yet. its been sitting in my room with no oil on it for a couple weeks now and i dont see any rust. thats the extent of my testing on that subject.
I bought this because i wanted a "tactical" shotgun without having to do all the mods myself. it already comes with a pistol grip and an extended capacity, the 2 things i wanted in my first shotgun.