Looks also like the very last production day of January - last VIN out according to other threads was 589720 for January, so this car is 303 away from January 31st, Feb. 1 or 2 for the last of the production week. 912/day, so pretty late January 01C. My Z is an 01C, body code starts with 229 (this one is 231), MSO is Jan. 28th. Dates/numbers support themselves, as was stated.
Regards,
Steve