There should be a VIN tag on the driver’s side of the firewall. The frame number will be located on the outside of the driver’s side frame rail forward of the front axle. They’re stamped kind of light so it might take some scraping and cleaning to see it. As I recall it should be 7 digits.

If you got a title with the truck and the VIN on the title doesn’t match the frame number there is a good chance the truck was titled using the engine number.

By the way looks like a good start on a project. I need to get motivated on my 37 Dodge truck project again…..