back in the 1980's, there were a lot of "grey market" chips. technically these weren't counterfeit chips, but they were fab rejects because they failed testing. so they were the real thing, but they were out of spec. some enterprising people went around to the fabs and bought the rejects for less than cost, and unbeknownst to the fab, resold them at full price... it didn't dawn on the fabs that these rejects might show up later on their doorstep(s) as batches of parts rejected by major equipment manufacturers... the lot and date codes matched the codes on the rejects sold to the shady resellers, and at that time a lot of fabs stopped selling reject parts, and began recycling the materials. i forget what magazine the article was in, but it was a far-east industry magazine in 1985 or so...