CCKW Odometers readings

[RANGER]

Trucks that were 40s-50s surplus and have remained in the US have the best chance of having the original mileage recorded. There is always the possibility of the vehicle bein operated for years with a broken cable or that the Speedometer head as been replaced at some time.
The surplus trucks from Europe that have been rebuilt may have replacement speedometers, and some are Metric. There is no way to calculate accurate mileage. Do not assume that because your truck has a speedometer showing 300 miles, that it means 300 miles since the truck was totally rebuilt. The French Army was famous for replacing worn parts with almost worn(serviceable) out parts.