I understand the concept of they were punched by hand and sometimes the punch moved a bit if they had to punch more then once. I guess what I really dont understand is how can there be example FS-01-1960D and there is more then one of them. wouldnt each RPM be different if it was done by hand? what are the chances that who ever was doing that job moved the punch the same way each time ?
I hope I understand your question correctly or this will sound really stupid. The hand punching takes place on the die, not the coin. So, they might hand punch the MM on a die and then use that die to mint thousands of coins. Any error when the MM was punched would be reproduced every time a coin was stamped with that die. That is how I understand it to work. If I am wrong in any area these guys will know and set me straight.
If I misunderstood your confusion and that does not answer your question, please let me know. Thanks!