I think that if there is a presence of US made parts that are accurate reproductions of foreign parts, that would create a reasonable doubt to any evidence in prosecution of a 922r violation.
So I'd have to say I agree with JTEX53 about the chances of 922r prosecution. If you're arrested on another, more easily proven weapons charge, they'll add the 922r charge regardless of whether the weapon is or is not compliant. Otherwise, they probably can't make any 922r charge stick.
Would making a weapon with largely foreign parts be illegal? Absolutely.
Do I condone, recommend, or support doing this? Absolutely not, it's still illegal.
But your chances of getting caught, found guilty, and sent to jail on 922r? I have to be honest here, I really don't think it'll happen unless you've committed some other crime.