Waynestewart was nice enough to let me come in and spend a few minutes pulling, dumping and comparing the EPROM from his good drive to compare with mine.

The results were fairly conclusive on the verify that even though the markings on both of our chips were different, their contents matched.....so the bit rot theory has been thrown out the window.

This goes back to the other possibility that there is a fault somewhere on my drive's logic board however we were not prepared to do a board swap and test this while at his house. Anyone willing to send me a board from a unformatable/crashed drive?