Date code question

2602 = Sept 11 1968

From the info I have, 2801543 would not have come in an A body BB car, it's a 2 barrel carb transmission. Also shows for a 67-68 model year car. I'll guess it's missing a 2 in front of the 406 which would make a build date of 2/28/68. It doesn't have a VIN, how can it be an "all numbers matching" deal?