I've seen a date on a LA built 70 Cuda that's about 80 cars before your vin. It was built 12/18/69. Of course, the cars weren't built in exact VIN sequence and even the fender tag dates were 'scheduled dates' and not always the actual date, but yours is probably not far off. Certainly December and most likely within a couple days either way of 12/18, if not the same day.