Well, I am thinking that since the PC is now basically a parts deal, and supposedly a very good deal on top of that, we are not talking about much money anyway. But I would be curious to know the sum of the parts and what the price asking is, to be sure I am giving sound advice.
I think you gave him good advice. But, it all depends on how honest the seller is. Without the feedback of e-bay, who knows?
The op can check out the actual sales of the interesting parts by looking at the completed auctions on e-bay.
If the deal is good enough, he can take a chance because there is not that much money involved.
OTOH if it sounds too good to be true, it probably is.