It's not so much chinese pistol and US parts, but more affordable pistol and avaialble parts.
Other than as little light stoning to smooth out the warts, there's rarely a need to swap out the small parts in a Norinco. I've got a stocker here that's been doing medium beater duty for several years and about 10,000 rounds. Nothing has failed and nothing has broken...and the gun has never malfunctioned. Ever.
All I did was change the springs and install the firing pin stop...lightly stone the rough spots on the disconnect and sear, and clean up the barrel ramp a little...not because of a problem...but because it wasn't feeding my cast SWCs quite as smoothly as I like. It shoots about an inch above POA at 25 yards, and cleans the plate rack at that distance as long as I don't jerk the trigger.
Can't ask much more than that of a pistol that I gave 300 bucks for NIB.
Ugly is as ugly does, hey!