Joshua,
After a bit more research, your VIN should include a "letter" character just to the left of the "255..." that we can see in your picture (see screen grab of your picture with added red arrow).
Give that "Tech Tip" I mentioned above a try and show us what may be revealed and we can try and better lock down your info.
FWIW, the "255O" at the beginning of your pictured VIN indicates the frame is a 1955 2nd Series built at the Oakland assembly plant. The rest of the numbers after that would indicate what "unit number" it was coming off that assembly line. A letter "J" at the beginning of the stamping would confirm you have a "3600" 3/4 Ton truck chassis.
My info came from the
1955 2nd Series resource file at the GM Heritage Centers Vehicle Info Kit site.
Dan
