Counterfeit parts from China (mostly) are really common. We build stuff for the Air Force and you should see the "restrictions" Northrop-Grumman places on us with respect to that. Every single chip we buy must be serialized and X-rayed and supplied with the X-ray film or electronic image file (showing the S/Ns) and the data to trace every part back to its origin. That "costs a bit more," but evidently they think it's worth it and since they're paying the bills, we can't debate this. This restriction applies mostly to older parts; it doesn't apply to new Intel Xeon CPUs and stuff purchased directly from authorized U.S. Intel distributors. But it applies to everything that's old or EOL, including 386/486-series chips (long discontinued, but still part of these designs!) and even TTL gate arrays and stuff. Once stuff is discontinued from current manufacture, it's all suspect.