Location of Vin number on 68 340 block

I have been trying to find location of the vin number on my 68 340 block. I have been trying to verify if I have the original block. The numbers that are stamped on the raised pad on the block above the oil pan on passenger side are not legible. Is this the correct spot. Any other ways to tell if I have the original block. I have same question on the 727 as there is no numbers stamped on pad. Thanks