I'm no lawyer, so take that for what it's worth.
Those products are not controlled. You can ship them wherever you'd like.
It would be illegal for the person receiving them in NJ to mount the stock on an AR15, though. He would likely get nailed for having it in the same house as a "regular" NJ-legal AR.
So long as the lower parts kit is for a modern semi-auto, I don't think it would be an issue. AR-style guns are legal in NJ so long as they don't have flash hiders, collapsable stocks, bayonet-lugs, etc. Remember the '94 ASW ban? It's still active in NJ.