Lemme see if I understand correctly.
I find a VIN (for a '68 just for talking purposes). It is 8N3xxxxx.
The last two numbers and the first of the last four numbers match.
So, it looks like this: 8N3x1x11 (I just picked 1, could be any other number).
Each 'x' can be any digit from 0 - 9. So, there are 100 possible VIN's that could be created by replacing each 'x' with digits from 0 - 9.
It gets worse - when the VIN turns from 8N3xxxxx to 8N4xxxxx - I get another 100 possible VIN's (actually less, since the last VIN wasn't 8N499999).
So, do I have a VIN match with the last two numbers and the first of the last four numbers matching?
Probably not.