Unmarked Carbine Parts

Recently I picked up some basically unmarked Carbine parts. Maybe not completely unmarked but I don't know enough about the markings to tell what they are.
First of all is a trigger housing, it looks to be milled, if it is a cast unit the finish is so good on it I can't see any casting marks. The only markings on it are one the left rear side, there is a capital N with a 9 about 1/4 below the N.
Then there are two barrels. The first is either new or freshly reparked. It has no markings or proof marks at all on it. It doesn't even have a witness mark. The bore looks new and the muzzle shows no wear at all. It also has the profile of a military barrel.
The second barrel is old, it has no finish left on it, but in fair shape as far as the bore goes. The only mark is an H inside a triangle on the flat right behind the gas piston. It has a strange profile as there is no hump in front of the threads.
Anyone have any clues on what these parts are? Thanks!

NPM trigger housing.