They're imported like this:
They have 0 US parts in this configuration and are only able to utilize their single stack mags.
So long as it's incapable of accepting a milsurp mag, it needs no US parts at all.
It looks like this.
Century has modified it since it was imported, but left the 10 round stinker magwell in place.
So long as you don't 'waller it out', you don't need any more US parts than what you have.
If you do open it up, you'll need another US part in the rifle, if it has a US made FCG and pistol grip already.
I still need to check the Piston to see if it