Originally Posted by
steveridessteel
The SN is a Olmo sequential number that has no date or model meaning but puts the frame in the 81 Olmo production time frame. It's pretty close to a Olmo Comp of that period with the addition of internal drive train routing. Let me know if you want additional info.
SN 56 1638
I think the first two digits indicate the frame size and the last four digits are the serial number.