Please help me decode this vin#. On the transferable registration for my '68 there are two stretches of numbers. One is 13 digits long and the other is 17 digits long. Here they both are. I'd appreciate any help. Which one is the VIN??

13 digits:
136378B216161

17 digits:
FB597391 KDI MED371

Thanks,
Chris

The vin has 13 digits. The others are possibly a title number.

136378B216161

The vin indicates a 1968 Malibu 2 dr sport couple with V8* engine built at Baltimore Assembly.

*Note-Optional engines are not coded, only base engines indicated by 3rd digit, odd=6; even=V8

Thank you both very much for the help!