There are only a few dist pad numbers on a '70 Hemi block, usually just the WT (water test) stamp and the assembly date.
The '66 and '67 had BH426 and CH426 stamps, the XH426 stamp was eliminated for '68 and up.
If no numbers at all exist, it's been decked.
It wasn't common for the dealer to restamp a VIN on a warranty block.