For serial number clarification:
Hobie Support Pages - Serial Numbers

The Serial number you have has some additional information that we no longer use. Hobie used to make "Seconds" or acceptable, but less than perfect hulls made available at a reduced cost. We also used a different format at that time.

The Serial number "CCMP8281M81G-A1"

Built in "M" Model Year
"81" 1981
"G" Production Month (A=August, B=September...)February 1981
"A-1" Second Quality.