Welcome to the site. Hope you find the information and support helpful in your concours focused needs.
As for earlier built cars you would need to contact and request a special report from Kevin Marti since he has access to all those historical records.
Not sure by your question if your looking and comparing all plants or just NJ
Just looking at the marti reports I found a 70 Dearborn car completed on 8/12/69 over a week before the one you posted