I have an early Intel SIM8-01 board that I am trying to date. I suspect that it was manufactured in mid-1972 but not sure. I have compared it to two other boards so far and found differences in the chip sets used and the actual circuit layout along with a few component differences. Also, my board has no serial number. I am interested in compiling a list of known boards along with serial numbers (if any), hardware differences, and chip types used. Send me a PM if you have one and I will send you some photos along with a description of my board for you to compare with yours.