In the tech sector, scams are not uncommon, and the electronics industry is no exception. One common scam involves changing the markings on chips to make them appear more valuable. The author had a personal experience with this when restoring an Acorn Atom. They purchased a Rockwell R65C02 chip, which was supposed to be a low-power CMOS variant of the original CPU. However, through testing, they discovered that the chip was actually a standard NMOS 6502. They also noticed discrepancies in the printing and date code, further confirming that the chip was fake. This problem of counterfeit chips is widespread and makes it difficult to find genuine parts. The author has even designed a prototype board to use a brand new 65C02 chip by Western Design Center in retro machines.
https://linuxjedi.co.uk/2023/12/01/fake-chips-i-got-stung/