I understand for 1970-1971 340 blocks, there are 2 vin pad locations?

-one above the oil pan on the passenger side and one under the driver side head in front of the block correct?

I asking because I was looking at a car and both pads have vin#'s stamped on them, but only one pad matches the vin tag.

Also, the casting for the block is 7 weeks later than the car's build date. Wouldn't that be alittle late (I mean as a "general" rule.....I know there are exceptions it seems to everything)

Thank you for any help!