I bought mine for a little local Mom-n-Pop place.
When I bought my Celerons, I was more particular, because
there was a good chance someone had already tested the parts,
and taken all the good ones. Those L1 bridges on the AMDs
are a blessing in disguise. I think the chances that the
stores are doing any pretesting is very slim.
I asked the guy at the computer shop if he'd tried overclocking
any of his Durons, or if he was aware of any of his customers
overclocking. He said that he'd never tried it, but was
curious. I showed him the bridges and how it was done.
Even here around Austin, which has lots of little computer
stores and lots of computer nerds, I think the vast majority
of computers are being bought by people who just want it to
work. The overclockers are a very small minority.