VIN number question for a '54 Chevy

[KIILew]

Hello '47-'54 truck people:

I have a question concerning VIN/Serial numbers...

Many years ago, my father purchased a 1954 Chevrolet 3/4 ton pickup (not running nor licensed since 1979) from an older couple, and I am now realizing that the vehicle I.D. number as shown on the title does not resemble the number that shows on the serial number plate in the driver side door jamb.

The VIN on the title page reads: 84516DF54

The serial number in the truck's door jamb reads: J540013513

Otherwise, the description of the vehicle on the title seems to be consistent with the actual vehicle, and the truck's license plates agree with those shown on the title.

Can anyone give me any ideas as to why the numbers are different? Could the number on the title reflect some other kind of serial or I.D. number marked elsewhere on the vehicle?