Yes it's an FX.
Opinion well it depends on what you plan to use it for and how much it's costing.
If it's for a display i would definitely want something more accurate.
For trooping in i think the armour is pretty good not the best but is passable although far from accurate but your average Joe on the street wouldn't know you should change the helmet for a movie sized lid the FX one is way too big.
I don't know what price you've been offered but the prices i see these regularly sell for is comparable to an unbuilt AP kit if you don't mind doing a whole lot of trimming and sanding the AP is a far nicer suit.
Thats my 2 cents