1951, 1952, 1953 VIN

[nickg112]

Over the years I have owned several Chevys from 51-54. I have noticed stamping of the VIN on the tag in the door frame varies somewhat. I see the following:

 

• ten numbers and letters in a straight row with no spaces (no photo attached)
• after the first letter, a small space followed by 9 numbers and letters (photo attached)
• after the 4th letter, a space and then 6 numbers (photo attached)

I know what each number and letter decode is but that is not the problem or my question. 

Which one of the three above is correct? Or are they all correct? Could the difference just be in differences in the factory procedures?

Photos below