Yes the serial is a true bolt number....
1KPF5975
Using the online decoder I discovered this about the truck....

Serial # : 1KPF5975
Mfg Date : June,1952
Model : 3100 1/2 ton
Wheelbase : 116 inches
Plant : Flint, MI

I thought that a repro plate was illegal? 'course I've already alerted the authorities with all my questions. Or does the repro plate fall under the 'don't ask don't tell'?

Ok, just got a call from the State and they said that the engine number was used prior to 1955 and has to agree with the title instead of the serial number plate. 'course that raises the question is the engine still the original engine? Fat chance after 55 years.

Would the block number agree with the serial number originally?

Thanks, Wade

More fun and games.