I think $1800 or $2k is above market value for sure. There are still other ways of getting it done without over paying for it.
Better just to buy a NSR with Cali registration and pay $500 or even a $1000 more as they are still out there.
I see that the frame buyer also bought the engine for way too much money IMO considering it needs a rebuild.
Maybe he thinks he's getting a deal piece by piece but I think he'll be way over what a clean one ready to ride would have cost him.