55.2-59 Need VIN help

[cigar-]

I have an opportunity on a 1957 GMC C30 truck. Of course it has no title! The seller has very little to offer me so I am starting with the VIN situation.

He has sent me a photo of a plaque that contains a serial number and weight information. See photo attached/enclosed. My internet search tells me the VIN is located in three places on the frame. "IF" that's the truth, we know where to look.

What I need to know is how many characters are in the VIN for a 1957 truck? Is there a standard prefix? Like do all VINs begin with a series of numbers and letters? example 1S23Bxxxxxxxxx