You already know the answer. Unless you can have him send you his computer first don't do it. There is WAY too big a risk here. The same thing happened to me with a gas powered RC car. I thought I was getting a deal too good to be true and ended up loosing 300 dollars.
Antec Super Lanboy
AMD 64 3800 S-939 Newcastle
MSI K8N Neo2 Platinum
1.5 GB pc 3200
WD 160 GB IDE
Viewsonic 22\" Widescreen 1680x1050
Coming Soon: Athlon 64 4000 San Diego/Z-5500/G7/Vista