Tony

I think it is early in January 1972. 0538 and 0550 were completed on 14 Jan but that may not be the best comparison as they were both ST's and (at least for the last part of their construction) would have been completed on a different production line. However one of those also has a production number very close to yours (within 10) which may be a better indication of when the production of the car was commenced
Also the little spec book says that the last 911S completed on Dec 31 1971 was 230 0489 However in all of these comparisons it is important to note that they are not completed in vin order.
To add a bit of extra data 0415 was a December car and 0576 was a January car.